a brief overview of transition metal photoredox catalysis...
TRANSCRIPT
A brief overview of Transition Metal Photoredox Catalysis as a tool for organic synthesis
Literature Review PresentationDimitri Caputo
7th December 2016
1. Introduction
2. Photoredox catalysis
3. Functional group interconversion
4. C-C bond formation
5. Conclusions
Outline
Contemporary definition
“Photoredox catalysis is a branch of catalysis that harnesses the energy of visible light to accelerate a chemical reaction via a single-electron transfer.”
- Wikipedia
“In a general sense, this approach relies on the ability of metal complexes and organic dyes to engage in single-electron transfer processes with organic substrates upon photoexcitation with visible light.”
-MacMillan
Early reports: late 1950’s
Introduction
Fe3+
Methylene blueEDTA
1,10-phenantroline
acetate buffer, pH 5visible light
Fe2+
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322G. K. Oster, G. Oster, J. Am. Chem. Soc., 1959, 81, 5543
Contemporary definition
“Photoredox catalysis is a branch of catalysis that harnesses the energy of visible light to accelerate a chemical reaction via a single-electron transfer.”
- Wikipedia
“In a general sense, this approach relies on the ability of metal complexes and organic dyes to engage in single-electron transfer processes with organic substrates upon photoexcitation with visible light.”
-MacMillan
Early reports: late 1950’s
Introduction
Fe3+
Methylene blueEDTA
1,10-phenantroline
acetate buffer, pH 5visible light
Fe2+
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322
Contemporary definition
“Photoredox catalysis is a branch of catalysis that harnesses the energy of visible light to accelerate a chemical reaction via a single-electron transfer.”
- Wikipedia
“In a general sense, this approach relies on the ability of metal complexes and organic dyes to engage in single-electron transfer processes with organic substrates upon photoexcitation with visible light.”
-MacMillan
Early reports: late 1950’s
Introduction
Fe3+
Methylene blueEDTA
1,10-phenantroline
acetate buffer, pH 5visible light
Fe2+
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322G. K. Oster, G. Oster, J. Am. Chem. Soc., 1959, 81, 5543
Applications in CO2 reduction, radical polymerization initiation…
Early applications in organic chemistry:
How does it work?
Introduction
CO2
[Ru(bpy)3]Cl2[Ru(bpy)2(CO)2](PF6)2
TEOA/DMF
visible lightHCOO- EtO
OBr
Ph O OMe
Ir(ppy)3
DMF, RTvisible light
EtO
O
Ph
Br
OMeO
n
J. W. Tucker, C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617-1622H. Ishida, T. Terada, K. Tanaka, T. Tanaka, Inorg. Chem., 1990, 29, 905-911B. P. Fors, C. J. Hawker, Angew. Chem. Int. Ed., 2012, 51, 8850-8853
S+R2R1
R3 N
COOEtEtOOC [Ru(bpy)3]Cl2
25°C, room light20 min, MeCN
100%
N+
EtOOC COOEtR1 H S R3R2
Applications in CO2 reduction, radical polymerization initiation…
Early applications in organic chemistry:
How does it work?
Introduction
CO2
[Ru(bpy)3]Cl2[Ru(bpy)2(CO)2](PF6)2
TEOA/DMF
visible lightHCOO- EtO
OBr
Ph O OMe
Ir(ppy)3
DMF, RTvisible light
EtO
O
Ph
Br
OMeO
n
J. W. Tucker, C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617-1622H. Ishida, T. Terada, K. Tanaka, T. Tanaka, Inorg. Chem., 1990, 29, 905-911B. P. Fors, C. J. Hawker, Angew. Chem. Int. Ed., 2012, 51, 8850-8853
S+R2R1
R3 N
COOEtEtOOC [Ru(bpy)3]Cl2
25°C, room light20 min, MeCN
100%
N+
EtOOC COOEtR1 H S R3R2
Publications in the field: exponential increase since 2008
Citation report from Web Of ScienceTM, Basic search by topic with “photoredox”, 23rd November 2016
Applications in CO2 reduction, radical polymerization initiation…
Early applications in organic chemistry:
How does it work?
Introduction
CO2
[Ru(bpy)3]Cl2[Ru(bpy)2(CO)2](PF6)2
TEOA/DMF
visible lightHCOO- EtO
OBr
Ph O OMe
Ir(ppy)3
DMF, RTvisible light
EtO
O
Ph
Br
OMeO
n
J. W. Tucker, C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617-1622H. Ishida, T. Terada, K. Tanaka, T. Tanaka, Inorg. Chem., 1990, 29, 905-911B. P. Fors, C. J. Hawker, Angew. Chem. Int. Ed., 2012, 51, 8850-8853
S+R2R1
R3 N
COOEtEtOOC [Ru(bpy)3]Cl2
25°C, room light20 min, MeCN
100%
N+
EtOOC COOEtR1 H S R3R2
Photoredox catalysis: general process
“Transition metal mediated photoredox catalysis”, S. Crossley, Shenvi Lab Group Meeting, 14/09/2015J. W. Tucker, C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617-1622
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322
P P*hν
D
A
ET
P D
P A
S
S
P DS
P AS
ET
ET
P DS
P AS
reductive quenching
oxidative quenching
P = photocatalyst, photoredox catalystD = electron donor species (amine, alcohol, thiol, electron-rich arene…)
A = electron acceptor species (carbonyl, halide, electron-poor arene)S = Redox neutral substrate
P
P*
P* P
PA A
D D
Photoredox catalysis: general process
“Transition metal mediated photoredox catalysis”, S. Crossley, Shenvi Lab Group Meeting, 14/09/2015J. W. Tucker, C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617-1622
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322
P P*hν
D
A
ET
P D
P A
S
S
P DS
P AS
ET
ET
P DS
P AS
reductive quenching
oxidative quenching
P = photocatalyst, photoredox catalystD = electron donor species (amine, alcohol, thiol, electron-rich arene…)
A = electron acceptor species (carbonyl, halide, electron-poor arene)S = Redox neutral substrate
P
P*
P* P
PA A
D D
Photoredox catalysis: what about the catalyst?
Ru
NN
NN
N
N
2 Cl-
O
O
O
Br
HOBr Br
OH
Br
Metal-ligand complex Organic dye
http://www.shsu.edu/~chm_tgc/chemilumdir/JABLON.GIF
TM Photoredox catalysis: metals and ligands
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
Mostly Ru2+ and Ir3+
Electronic configuration
Ru2+: [Kr]3f144d6 Ir3+: [Xe]4f145d6
d6 complexes
Ligand field theory:
d orbitals
x L
Ligand field stabilisation engery
eg
t2g
Octahedral complexeslow-spin d6 state
substitutionally inert
Mn+ MLxn+
TM Photoredox catalysis: metals and ligands
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
Mostly Ru2+ and Ir3+
Electronic configuration
Ru2+: [Kr]3f144d6 Ir3+: [Xe]4f145d6
d6 complexes
Ligand field theory:
d orbitals
x L
Ligand field stabilisation engery
eg
t2g
Octahedral complexeslow-spin d6 state
substitutionally inert
Mn+ MLxn+
TM Photoredox catalysis: metals and ligands
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
Mostly Ru2+ and Ir3+
Electronic configuration
Ru2+: [Kr]3f144d6 Ir3+: [Xe]4f145d6
d6 complexes
Ligand field theory:
d orbitals
x L
Ligand field stabilisation engery
eg
t2g
Octahedral complexeslow-spin d6 state
substitutionally inert
Mn+ MLxn+
TM Photoredox catalysis: intrinsic properties of metal
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015“Chemistry: Principles, Patterns, and Applications”, Chapter 23, B. A. Averill, P. Eldredge,
RuII
NN
NN
N
N
Ru(bpy)32+
IrIII
NN
NN
N
N
Ir(bpy)33+
Ru(II)*/Ru(III) = − 0.81 VRu(II)*/Ru(I) = 0.77 V
Ir(III)*/Ir(IV) = − 0.88 VIr(III)*/Ir(II) = 1.81 V
Similar reducing properties
Ir complex stronger oxidant than Ru complex
(same set of ligand)
RuN
N
NN
NN N
N
N
N
NN
2+
Ru
N
N
N
N
N
NN
N
N
N
N
N
2+
RuN
N
NN
NN
2+
RuN
N
NN
NN
2+
IrNN
N
F F
F
FF
F
IrNN
NN
F F
F
F
CF3
F3C
tBu
tBu
3+
3+
1+
IrNN
NN
tBu
tBu
3+
IrNN
N
3+
NMe
Me
Me
Me
ClO4-
O
BF4-O O
CO2H
HOBr
Br
Br
Br
Eosin Y
Et (S*/S )Eo (S/S )
0.79V-1.06V
lmax 539 nm
O O
CO2H
HO
Fluorescein
Et (S*/S )Eo (S/S )
0.78V-1.27V
lmax 528 nm
lmax 443 nm
Ru(bpz)32+ = Ru(II)Ru(II)*/Ru(I) = 1.45V
Ru(II)*/Ru(III) = -0.26VRu(II)/Ru(I) = -0.80VRu(III)/Ru(II) = 1.86V
2+ 2+ 2+
Ru(bpm)32+ = Ru(II)Ru(II)*/Ru(I) = 0.99V
Ru(II)*/Ru(III) = -0.21VRu(II)/Ru(I) = -0.91VRu(III)/Ru(II) = 1.69V
Ru(bpy)32+ = Ru(II)Ru(II)*/Ru(I) = 0.77V
Ru(II)*/Ru(III) = -0.81VRu(II)/Ru(I) = -1.33VRu(III)/Ru(II) = 1.29V
Ru(phen)32+ = Ru(II)Ru(II)*/Ru(I) = 0.82V
Ru(II)*/Ru(III) = -0.87VRu(II)/Ru(I) = -1.36VRu(III)/Ru(II) = 1.26V
2+
f ac-Ir(dF-ppy)33+ = Ir(III)Ir(III)/Ir(II) = -2.11VIr(IV)/Ir(III) = 1.18V
Ir(dF-CF3-ppy)2(dtbpy)3+ = Ir(III)Ir(III)*/Ir(II) = 1.21V
Ir(III)*/Ir(IV) = -0.89VIr(III)/Ir(II) = -1.37VIr(IV)/Ir(III) = 1.69V
Ir(ppy)2(dtbpy)3+ = Ir(III)Ir(III)*/Ir(II) = 0.66V
Ir(III)*/Ir(IV) = -0.96VIr(III)/Ir(II) = -1.51VIr(IV)/Ir(III) = 1.21V
f ac-Ir(ppy)33+ = Ir(III)Ir(III)*/Ir(II) = 0.31V
Ir(III)*/Ir(IV) = -1.73VIr(III)/Ir(II) = -2.19VIr(IV)/Ir(III) = 0.77V
lmax 380 nm
lmax 454 nm
lmax 422 nm lmax 375 nm
lmax 347 nm
lmax 380 nm
lmax 452 nm
lmax 430 nm
lmax 417 nm
Et (S*/S )Eo (S/S )
2.3V (T1)-0.35 V
1+
1+
Et (S*/S )Eo (S/S )
2.06V-0.57V
Mes-Acr+
Triphenylpyrylium
E* (V vs SCE))
+2.5 05.0+0.1+5.1+0.2+
Me
Me
Me
OMe HN
2.30V
Me
2.28V
1.21V1.76V
0.96
0.98V
NH2
Me
O
-O1.24V
PhMe
1.60V
1.81V
Et3N
S2.15V
MeS
1.63V
Ph
-2.5-0.5 0.2-5.1-0.1-0
IrNN
N
3+
f ac-Ir(ppy)33+ = Ir(III)Ir(III)*/Ir(II) = 0.31V
Ir(III)*/Ir(IV) = -1.73VIr(III)/Ir(II) = -2.19VIr(IV)/Ir(III) = 0.77Vlmax 375 nm
IrNN
N
F F
F
FF
F
3+
f ac-Ir(dF-ppy)33+ = Ir(III)Ir(III)/Ir(II) = -2.11VIr(IV)/Ir(III) = 1.18V
lmax 347 nm
1+
IrNN
NN
tBu
tBu
3+
Ir(ppy)2(dtbpy)3+ = Ir(III)Ir(III)*/Ir(II) = 0.66V
Ir(III)*/Ir(IV) = -0.96VIr(III)/Ir(II) = -1.51VIr(IV)/Ir(III) = 1.21Vlmax 380 nm
1+
RuN
N
NN
NN
2+
Ru(phen)32+ = Ru(II)Ru(II)*/Ru(I) = 0.82V
Ru(II)*/Ru(III) = -0.87VRu(II)/Ru(I) = -1.36VRu(III)/Ru(II) = 1.26V
2+
lmax 422 nm
IrNN
NN
F F
F
F
CF3
F3C
tBu
tBu
3+
1+
Ir(dF-CF3-ppy)2(dtbpy)3+ = Ir(III)Ir(III)*/Ir(II) = 1.21V
Ir(III)*/Ir(IV) = -0.89VIr(III)/Ir(II) = -1.37VIr(IV)/Ir(III) = 1.69V
lmax 380 nm
RuN
N
NN
NN
2+
2+
Ru(bpy)32+ = Ru(II)Ru(II)*/Ru(I) = 0.77V
Ru(II)*/Ru(III) = -0.81VRu(II)/Ru(I) = -1.33VRu(III)/Ru(II) = 1.29V
lmax 452 nm
O O
CO2H
HO
Fluorescein
Et (S*/S )Eo (S/S )
0.78V-1.27V
lmax 528 nm
O O
CO2H
HOBr
Br
Br
Br
Eosin Y
Et (S*/S )Eo (S/S )
0.79V-1.06V
lmax 539 nm
Ru
N
N
N
N
N
NN
N
N
N
N
N
2+
2+
Ru(bpm)32+ = Ru(II)Ru(II)*/Ru(I) = 0.99V
Ru(II)*/Ru(III) = -0.21VRu(II)/Ru(I) = -0.91VRu(III)/Ru(II) = 1.69V
lmax 454 nm
RuN
N
NN
NN N
N
N
N
NN
2+
lmax 443 nm
Ru(bpz)32+ = Ru(II)Ru(II)*/Ru(I) = 1.45V
Ru(II)*/Ru(III) = -0.26VRu(II)/Ru(I) = -0.80VRu(III)/Ru(II) = 1.86V
2+
NMe
Me
Me
Me
ClO4-
lmax 430 nm
Et (S*/S )Eo (S/S )
2.06V-0.57V
Mes-Acr+
O
BF4-
lmax 417 nm
Et (S*/S )Eo (S/S )
2.3V (T1)-0.35 V
Triphenylpyrylium
N
N
-2.08V
Ph
O
Me-2.14V
Ph
O
H-1.93V
Ph
O
OH-2.24V
OO
-0.45V
I
-1.16V
Br
-1.76V Cl
-2.09V
OO
O-0.85V
NO
-2.30V
N3
O2N-0.83V
F3C SO
OCl
-0.18V
-1.22V
CF3I
E* (V vs SCE))
I
-2.33V-1.71V
Ph Br
Ph
OBr
-0.49V
Electrochemical Series of Photocatalysts and Common Organic Compounds
Excited State Oxidations Reduced State Reductions
compiled by D. DiRocco 2014
TBPA = 1.05V
O
O
CN
CN
Cl
Cl
DDQ = 0.53V
N
Br
Br
Br
CAN = 0.96V(NH4)2[Ce(NO3)6]persulfate= 2.36V
SO4
persulfate = 1.85V
S2O8F FFluorine = 2.62V
H2O2hydrogen peroxide = 1.45V
MnO4permanganate = 1.43V
O O
oxygen = 0.99V
Agsilver(I) = 0.6V
Sm(II)I2 = -1.65V
Copper(II)= 0.28V
Hypochlorite = 1.39VHOCl Irono = -0.65V Zinco = -1.00V
Magnesiumo = -2.62V
Sodiumo = -2.95V
Lithiumo = -3.28V(2e-)
(2e-)
(2e-)
(2e-)
(1e-)
(4e-)
(2e-)
(2e-) (2e-) (4e-)
ascorbic acid = -0.19V
dithionite = -0.77VS2O42-
(2e-)
O
OHHO
O
OHHO
H
Common Oxidizing Agents Common Reducing Agents
TM Photoredox catalysis: metals and ligands
RuII
NN
NN
N
NRuII
N
N
NN
NNN
N
NN
NN
RuII
N
N
N
N
N
NN
N
NN
NNRuII
NN
NN
N
N
IrIIIN
N
NIrIII
N
N
NIrIII
N
NN
NIrIII
N
NN
N
F
F
F
F
F
F
F
F
FF
tBu
tBu tBu
tBu
Ru(bpy)32+ Ru(bpz)32+ Ru(bpm)32+ Ru(phen)32+
fac-Ir(ppy)3 fac-Ir(dF-ppy)3 Ir(dF-CF3-ppy)2(dtbpy)+ Ir(ppy)2(dtbpy)+
CF3
F3C
TM Photoredox catalysis: metals and ligands
RuII
NN
NN
N
NRuII
N
N
NN
NNN
N
NN
NN
RuII
N
N
N
N
N
NN
N
NN
NNRuII
NN
NN
N
N
IrIIIN
N
NIrIII
N
N
NIrIII
N
NN
NIrIII
N
NN
N
F
F
F
F
F
F
F
F
FF
tBu
tBu tBu
tBu
Ru(bpy)32+ Ru(bpz)32+ Ru(bpm)32+ Ru(phen)32+
fac-Ir(ppy)3 fac-Ir(dF-ppy)3 Ir(dF-CF3-ppy)2(dtbpy)+ Ir(ppy)2(dtbpy)+
CF3
F3C
TM Photoredox catalysis: metals and ligands
Ru complexes: homoleptic Ir complexes: homoleptic
and heteroleptic
RuII
NN
NN
N
NRuII
N
N
NN
NNN
N
NN
NN
RuII
N
N
N
N
N
NN
N
NN
NNRuII
NN
NN
N
N
IrIIIN
N
NIrIII
N
N
NIrIII
N
NN
NIrIII
N
NN
N
F
F
F
F
F
F
F
F
FF
tBu
tBu tBu
tBu
Ru(bpy)32+ Ru(bpz)32+ Ru(bpm)32+ Ru(phen)32+
fac-Ir(ppy)3 fac-Ir(dF-ppy)3 Ir(dF-CF3-ppy)2(dtbpy)+ Ir(ppy)2(dtbpy)+
CF3
F3C
TM Photoredox catalysis: usual ligand type
N
N
N
Type bpy neutral
LL
Type ppy anionic
LX
Strong e- donation Found in Ir3+ (better stabilisation)
Found in Ru2+
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015E. Y. Li, Y.-M. Cheng, C.-C. Hsu, P.-T. Chou, G.-H. Lee, Inorg. Chem., 2006, 45, 9631
P. G. Bomben, K. C. D. Robson, P. A. Sedach, C. P. Berlinguette, Inorg. Chem., 2009, 48, 9631
Heteroleptic complexes: Spin-Orbit coupling disrupted, MLCT less efficient SO (Ir) > SO (Ru) è compensation
Ru complexes mostly homoleptic and LL ligands
TM Photoredox catalysis: usual ligand type
N
N
N
Type bpy neutral
LL
Type ppy anionic
LX
Strong e- donation Found in Ir3+ (better stabilisation)
Found in Ru2+
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015E. Y. Li, Y.-M. Cheng, C.-C. Hsu, P.-T. Chou, G.-H. Lee, Inorg. Chem., 2006, 45, 9631
P. G. Bomben, K. C. D. Robson, P. A. Sedach, C. P. Berlinguette, Inorg. Chem., 2009, 48, 9631
Heteroleptic complexes: Spin-Orbit coupling disrupted, MLCT less efficient SO (Ir) > SO (Ru) è compensation
Ru complexes mostly homoleptic and LL ligands
TM Photoredox catalysis: usual ligand type
N
N
N
Type bpy neutral
LL
Type ppy anionic
LX
Strong e- donation Found in Ir3+ (better stabilisation)
Found in Ru2+
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015E. Y. Li, Y.-M. Cheng, C.-C. Hsu, P.-T. Chou, G.-H. Lee, Inorg. Chem., 2006, 45, 9631
P. G. Bomben, K. C. D. Robson, P. A. Sedach, C. P. Berlinguette, Inorg. Chem., 2009, 48, 9631
Heteroleptic complexes: Spin-Orbit coupling disrupted, MLCT less efficient SO (Ir) > SO (Ru) è compensation
Ru complexes mostly homoleptic and LL ligands
TM Photoredox catalysis: usual ligand type
N
N
N
Type bpy neutral
LL
Type ppy anionic
LX
Strong e- donation Found in Ir3+ (better stabilisation)
Found in Ru2+
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015E. Y. Li, Y.-M. Cheng, C.-C. Hsu, P.-T. Chou, G.-H. Lee, Inorg. Chem., 2006, 45, 9631
P. G. Bomben, K. C. D. Robson, P. A. Sedach, C. P. Berlinguette, Inorg. Chem., 2009, 48, 9631
Heteroleptic complexes: Spin-Orbit coupling disrupted, MLCT less efficient SO (Ir) > SO (Ru) è compensation
Ru complexes mostly homoleptic and LL ligands
TM Photoredox catalysis: heteroleptic VS homoleptic
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015A. B. Tamayo et al., J. Am. Chem. Soc., 2003, 125, 7377-7387
M. S. Lowry et al., Chem. Mater., 2005, 17, 5712-5719
Heteroleptic: spatial modification of HOMO/LUMO
IrIII
N
NN
IrIII
N
NN
N
tBu
tBu
IrIII
N
NN
IrIII
N
NN
N
tBu
tBu
Ir(ppy)3*
Ir(ppy)2(dtbbpy)*
HOMO LUMO
TM Photoredox catalysis: heteroleptic VS homoleptic
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015A. B. Tamayo et al., J. Am. Chem. Soc., 2003, 125, 7377-7387
M. S. Lowry et al., Chem. Mater., 2005, 17, 5712-5719
Heteroleptic: spatial modification of HOMO/LUMO
IrIII
N
NN
IrIII
N
NN
N
tBu
tBu
IrIII
N
NN
IrIII
N
NN
N
tBu
tBu
Ir(ppy)3*
Ir(ppy)2(dtbbpy)*
HOMO LUMO
TM Photoredox catalysis: effects of ligand on redox potentials
“Electrochemical Series of Photocatalysts and Common Organic Coumpounds”, D. DiRocco, 2014, Merck“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
IrIIIN
N
NIrIII
N
NN
NIrIII
N
NN
N
F
F
FF
tBu
tButBu
tBu
fac-Ir(ppy)3 Ir(dF-CF3-ppy)2(dtbpy)+Ir(ppy)2(dtbpy)+
CF3
F3C
Ir(III)*/Ir(IV) = − 1.73 VIr(III)*/Ir(II) = 0.31 V
Ir(III)*/Ir(IV) = − 0.96 VIr(III)*/Ir(II) = 0.66 V
Ir(III)*/Ir(IV) = − 0.89 VIr(III)*/Ir(II) = 1.21 V
IrIIIN
N
NIrIII
N
NN
NIrIII
N
NN
N
F
F
FF
tBu
tButBu
tBu
fac-Ir(ppy)3 Ir(dF-CF3-ppy)2(dtbpy)+Ir(ppy)2(dtbpy)+
CF3
F3C
Ir(III)*/Ir(IV) = − 1.73 VIr(III)*/Ir(II) = 0.31 V
Ir(III)*/Ir(IV) = − 0.96 VIr(III)*/Ir(II) = 0.66 V
Ir(III)*/Ir(IV) = − 0.89 VIr(III)*/Ir(II) = 1.21 V
TM Photoredox catalysis: effects of ligand on redox potentials
LL to LX ligand: electron density on the metal increases è Reductive power increases
“Electrochemical Series of Photocatalysts and Common Organic Coumpounds”, D. DiRocco, 2014, Merck“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
IrIIIN
N
NIrIII
N
NN
NIrIII
N
NN
N
F
F
FF
tBu
tButBu
tBu
fac-Ir(ppy)3 Ir(dF-CF3-ppy)2(dtbpy)+Ir(ppy)2(dtbpy)+
CF3
F3C
Ir(III)*/Ir(IV) = − 1.73 VIr(III)*/Ir(II) = 0.31 V
Ir(III)*/Ir(IV) = − 0.96 VIr(III)*/Ir(II) = 0.66 V
Ir(III)*/Ir(IV) = − 0.89 VIr(III)*/Ir(II) = 1.21 V
TM Photoredox catalysis: effects of ligand on redox potentials
LL to LX ligand: electron density on the metal increases è Reductive power increases EWG on ligands: electron density on the metal decreases è Oxidative power increases
“Electrochemical Series of Photocatalysts and Common Organic Coumpounds”, D. DiRocco, 2014, Merck“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
IrIIIN
N
NIrIII
N
NN
NIrIII
N
NN
N
F
F
FF
tBu
tButBu
tBu
fac-Ir(ppy)3 Ir(dF-CF3-ppy)2(dtbpy)+Ir(ppy)2(dtbpy)+
CF3
F3C
Ir(III)*/Ir(IV) = − 1.73 VIr(III)*/Ir(II) = 0.31 V
Ir(III)*/Ir(IV) = − 0.96 VIr(III)*/Ir(II) = 0.66 V
Ir(III)*/Ir(IV) = − 0.89 VIr(III)*/Ir(II) = 1.21 V
TM Photoredox catalysis: effects of ligand on redox potentials
LL to LX ligand: electron density on the metal increases è Reductive power increases EWG on ligands: electron density on the metal decreases è Oxidative power increases
TM/ligand complexes = tunable catalysts
“Electrochemical Series of Photocatalysts and Common Organic Coumpounds”, D. DiRocco, 2014, Merck“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
Photoredox catalysis: active species
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322-5363“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
N. H. Damrauer, G. Cerullo, A. Yeh, T. R. Boussie, C. V. Shank, J. K. McCusker, Science, 1997, 275, 54-57
τ(1MLCT) < τ(3MLCT)
3MLCT active species = P*
[Ru(bpy)3]Cl2octahedral, d6
low-spin configuration(substitutionally inert)
λmax = 452 nm
RuII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Ground state Excited singlet state 1MLCTτ = 100-300 10-15 s
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Excited triplet state 3MLCTτ = 1100 10-9 s
Photon absorption
MLCT
ISC
Photoredox catalysis: active species
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322-5363“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
N. H. Damrauer, G. Cerullo, A. Yeh, T. R. Boussie, C. V. Shank, J. K. McCusker, Science, 1997, 275, 54-57
τ(1MLCT) < τ(3MLCT)
3MLCT active species = P*
[Ru(bpy)3]Cl2octahedral, d6
low-spin configuration(substitutionally inert)
λmax = 452 nm
RuII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Ground state Excited singlet state 1MLCTτ = 100-300 10-15 s
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Excited triplet state 3MLCTτ = 1100 10-9 s
Photon absorption
MLCT
ISC
Photoredox catalysis: active species
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322-5363“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
N. H. Damrauer, G. Cerullo, A. Yeh, T. R. Boussie, C. V. Shank, J. K. McCusker, Science, 1997, 275, 54-57
τ(1MLCT) < τ(3MLCT)
3MLCT active species = P*
[Ru(bpy)3]Cl2octahedral, d6
low-spin configuration(substitutionally inert)
λmax = 452 nm
RuII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Ground state Excited singlet state 1MLCTτ = 100-300 10-15 s
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Excited triplet state 3MLCTτ = 1100 10-9 s
Photon absorption
MLCT
ISC
Photoredox catalysis: active species
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322-5363“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
N. H. Damrauer, G. Cerullo, A. Yeh, T. R. Boussie, C. V. Shank, J. K. McCusker, Science, 1997, 275, 54-57
τ(1MLCT) < τ(3MLCT)
3MLCT active species = P*
[Ru(bpy)3]Cl2octahedral, d6
low-spin configuration(substitutionally inert)
λmax = 452 nm
RuII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Ground state Excited singlet state 1MLCTτ = 100-300 10-15 s
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Excited triplet state 3MLCTτ = 1100 10-9 s
Photon absorption
MLCT
ISC
Photoredox catalysis: active species
C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322-5363“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015
N. H. Damrauer, G. Cerullo, A. Yeh, T. R. Boussie, C. V. Shank, J. K. McCusker, Science, 1997, 275, 54-57
τ(1MLCT) < τ(3MLCT)
3MLCT active species = P*
[Ru(bpy)3]Cl2octahedral, d6
low-spin configuration(substitutionally inert)
λmax = 452 nm
RuII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Ground state Excited singlet state 1MLCTτ = 100-300 10-15 s
RuIII
NN
NN
N
N
2 Cl-
eg*
π*
t2g*
Excited triplet state 3MLCTτ = 1100 10-9 s
Photon absorption
MLCT
ISC
Photoredox catalysis: Thermodynamics and kinetics
“Behind the scenes with Transition Metal Photocatalysts”, E. R. Welin, MacMillan Group Meetings, 12/02/2015C. K. Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev., 2013, 113, 5322-5363
J. W. Tucker, C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617-1622
Ru(bpy)32+
1Ru*(bpy)32+
3Ru*(bpy)32+
Ru(bpy)3+ Ru(bpy)33+
hν
ISCRu*(II)/Ru(I) = 0.77 V
Ru(II)/Ru(I) = -1.33 V Ru(III)/Ru(II) = 1.29 V
Ru(III)/Ru*(II) = -0.81 V
Reductive quenching Oxidative quenching
Ru(bpy)32+
1Ru*(bpy)32+
3Ru*(bpy)32+
Ru(bpy)3+ Ru(bpy)33+
hν
ISCRu*(II)/Ru(I) = 0.77 V
Ru(II)/Ru(I) = -1.33 V Ru(III)/Ru(II) = 1.29 V
Ru(III)/Ru*(II) = -0.81 V
Reductive quenching Oxidative quenching
Photoredox catalysis: Thermodynamics and kinetics
R. A. Marcus, J. Chem. Phys., 1956, 24, 966 A Very Brief Introduction of the Concepts of Marcus Theory, V. Shurtleff, MacMillan Group Meetings, 26/06/2016
J. W. Tucker, C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617-1622
Ru(bpy)32+
1Ru*(bpy)32+
3Ru*(bpy)32+
Ru(bpy)3+ Ru(bpy)33+
hν
ISCRu*(II)/Ru(I) = 0.77 V
Ru(II)/Ru(I) = -1.33 V Ru(III)/Ru(II) = 1.29 V
Ru(III)/Ru*(II) = -0.81 V
Reductive quenching Oxidative quenching
Photoredox catalysis: Thermodynamics and kinetics
R. A. Marcus, J. Chem. Phys., 1956, 24, 966 A Very Brief Introduction of the Concepts of Marcus Theory, V. Shurtleff, MacMillan Group Meetings, 26/06/2016
J. W. Tucker, C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617-1622
Beware of the Marcus inversion
Functional group interconversion
Reduction of electron-deficient olefins
C. Pac, M. Ihama, M. Yasuda, Y. Miyauchi, H. Sakurai, J. Am. Chem. Soc., 1981, 103, 6495-6497
CN
NC
CN
H3CO
Ph PhCN
61% 33%
33%
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N
NH2
O
BnBNAH
N
NH2
O
Bn
COOMeMeOOC
COOMeMeOOC
MeOOC COOMe
N
NH2
O
Bn
H+, e−
−e−
MeOOC COOMeN+
NH2
O
Bn
H+
−H+
• SM doesn’t quench *Ru(bpy)32+
è Reductive quenching • BNAH-4,4-d2: next to no deuteration CH3OD, CD3OD: deuteration
è Direct H transfer negligeable • Last ET from Ru(bpy)+ or BNA�
-1.33 V 0.77 V
0.76 V
-0.94 V
MeOOC COOMe
Ru(bpy)3Cl2 (2 mol%)BNAH (2.0 equiv.)
pyridine/MeOHvisible light, 96%
MeOOC
COOMe
Reduction of electron-deficient olefins
C. Pac, M. Ihama, M. Yasuda, Y. Miyauchi, H. Sakurai, J. Am. Chem. Soc., 1981, 103, 6495-6497
CN
NC
CN
H3CO
Ph PhCN
61% 33%
33%
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N
NH2
O
BnBNAH
N
NH2
O
Bn
COOMeMeOOC
COOMeMeOOC
MeOOC COOMe
N
NH2
O
Bn
H+, e−
−e−
MeOOC COOMeN+
NH2
O
Bn
H+
−H+
• SM doesn’t quench *Ru(bpy)32+
è Reductive quenching • BNAH-4,4-d2: next to no deuteration CH3OD, CD3OD: deuteration
è Direct H transfer negligeable • Last ET from Ru(bpy)+ or BNA�
-1.33 V 0.77 V
0.76 V
-0.94 V
MeOOC COOMe
Ru(bpy)3Cl2 (2 mol%)BNAH (2.0 equiv.)
pyridine/MeOHvisible light, 96%
MeOOC
COOMe
Reduction of electron-deficient olefins
C. Pac, M. Ihama, M. Yasuda, Y. Miyauchi, H. Sakurai, J. Am. Chem. Soc., 1981, 103, 6495-6497
CN
NC
CN
H3CO
Ph PhCN
61% 33%
33%
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N
NH2
O
BnBNAH
N
NH2
O
Bn
COOMeMeOOC
COOMeMeOOC
MeOOC COOMe
N
NH2
O
Bn
H+, e−
−e−
MeOOC COOMeN+
NH2
O
Bn
H+
−H+
• SM doesn’t quench *Ru(bpy)32+
è Reductive quenching • BNAH-4,4-d2: next to no deuteration CH3OD, CD3OD: deuteration
è Direct H transfer negligeable • Last ET from Ru(bpy)+ or BNA�
-1.33 V 0.77 V
0.76 V
-0.94 V
MeOOC COOMe
Ru(bpy)3Cl2 (2 mol%)BNAH (2.0 equiv.)
pyridine/MeOHvisible light, 96%
MeOOC
COOMe
Reduction of electron-deficient olefins
C. Pac, M. Ihama, M. Yasuda, Y. Miyauchi, H. Sakurai, J. Am. Chem. Soc., 1981, 103, 6495-6497
CN
NC
CN
H3CO
Ph PhCN
61% 33%
33%
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N
NH2
O
BnBNAH
N
NH2
O
Bn
COOMeMeOOC
COOMeMeOOC
MeOOC COOMe
N
NH2
O
Bn
H+, e−
−e−
MeOOC COOMeN+
NH2
O
Bn
H+
−H+
• SM doesn’t quench *Ru(bpy)32+
è Reductive quenching • BNAH-4,4-d2: next to no deuteration CH3OD, CD3OD: deuteration
è Direct H transfer negligeable • Last ET from Ru(bpy)+ or BNA�
-1.33 V 0.77 V
0.76 V
-0.94 V
MeOOC COOMe
Ru(bpy)3Cl2 (2 mol%)BNAH (2.0 equiv.)
pyridine/MeOHvisible light, 96%
MeOOC
COOMe
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
BrO
Ph
H H
N+
H+
O
PhO
Ph H
Reductive dehalogenation: activated halides
S. Fukuzumi, S. Mochizuki, T. Tanaka, J. Phys. Chem., 1990, 94, 722-726 S. Fukuzumi, S. Mochizuki, K. Hironaka, T. Tanaka, J. Am. Chem. Soc., 1987, 109, 305-316
BrO
Ph
Ru(bpy)3Cl2 (5 mol%)9,10-dihydro-10-methylacridine
MeCN, visible light
O
Ph
0.77 V
0.57-0.80 V
-0.49 V
-1.33 V
• Bromide doesn’t quench Ru(bpy)32+
è reductive quenching • Addition of HClO4: quenching by AcrH2 decreases
è AcrH2 à AcrH3+ (weaker reductant)
• More HClO4: increase of quenching and reaction conversion
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
BrO
Ph
H H
N+
O
PhO
Ph H
Reductive dehalogenation: activated halides
S. Fukuzumi, S. Mochizuki, T. Tanaka, J. Phys. Chem., 1990, 94, 722-726 S. Fukuzumi, S. Mochizuki, K. Hironaka, T. Tanaka, J. Am. Chem. Soc., 1987, 109, 305-316
BrO
Ph
Ru(bpy)3Cl2 (5 mol%)9,10-dihydro-10-methylacridine
MeCN, visible light
O
Ph
0.77 V
0.57-0.80 V
-0.49 V
-1.33 V
• Bromide doesn’t quench Ru(bpy)32+
è reductive quenching • Addition of HClO4: quenching by AcrH2 decreases
è AcrH2 à AcrH3+ (weaker reductant)
• More HClO4: increase of quenching and reaction conversion
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
BrO
Ph
H H
N+
O
PhO
Ph H
Reductive dehalogenation: activated halides
S. Fukuzumi, S. Mochizuki, T. Tanaka, J. Phys. Chem., 1990, 94, 722-726 S. Fukuzumi, S. Mochizuki, K. Hironaka, T. Tanaka, J. Am. Chem. Soc., 1987, 109, 305-316
BrO
Ph
Ru(bpy)3Cl2 (5 mol%)9,10-dihydro-10-methylacridine
MeCN, visible light
O
Ph
0.77 V
0.57-0.80 V
-0.49 V
-1.33 V
• Bromide doesn’t quench Ru(bpy)32+
è reductive quenching • Addition of HClO4: quenching by AcrH2 decreases
è AcrH2 à AcrH3+ (weaker reductant)
• More HClO4: increase of quenching and reaction conversion
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)33+
N
N
BrO
Ph
OH
Ph
H H
O
PhBr
N
−H+
N+
H+
Reductive dehalogenation: activated halides
S. Fukuzumi, S. Mochizuki, T. Tanaka, J. Phys. Chem., 1990, 94, 722-726 S. Fukuzumi, S. Mochizuki, K. Hironaka, T. Tanaka, J. Am. Chem. Soc., 1987, 109, 305-316
BrO
Ph
Ru(bpy)3Cl2 (5 mol%)9,10-dihydro-10-methylacridine
MeCN, visible light
O
Ph
• Large quantities of HClO4 è induces oxidative quenching
• Reduction of phenacyl chloride possible
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)33+
N
N
BrO
Ph
OH
Ph
H H
O
PhBr
N
−H+
N+
H+
Reductive dehalogenation: activated halides
S. Fukuzumi, S. Mochizuki, T. Tanaka, J. Phys. Chem., 1990, 94, 722-726 S. Fukuzumi, S. Mochizuki, K. Hironaka, T. Tanaka, J. Am. Chem. Soc., 1987, 109, 305-316
BrO
Ph
Ru(bpy)3Cl2 (5 mol%)9,10-dihydro-10-methylacridine
MeCN, visible light
O
Ph
• Large quantities of HClO4 è induces oxidative quenching
• Reduction of phenacyl chloride possible
Reductive dehalogenation: activated halides
J. M. R. Narayanam, J. W. Tucker, C. R. J. Stephenson, J. Am. Chem. Soc., 2009, 131, 8756–8757 U. Pischel et al., J. Am. Chem. Soc., 2000, 122, 2027-2043
N HHOH
O
0.68 V
0.77 V
R X
Ru(bpy)3Cl2 (2.5 mol%)i-Pr2NEt / HCOOH (10 equiv.)
ori-Pr2NEt (2.0 equiv.) / Hantzsch ester (1.1 equiv.)
DMF, rt, 4-24hvisible light
R H
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
RX
R
N+
RH
H
NBoc
NCOOMe
COOMeH
H
95%
O N
Bn
O O
HPh
OH
95% from Br80% from Cl
I
O
OPh
HO
OPh
H
I O
OPh
H
88% from ClHantzsch ester
81% from ClHantzsch ester
89% from ClHantzsch ester
Reductive dehalogenation: activated halides
J. M. R. Narayanam, J. W. Tucker, C. R. J. Stephenson, J. Am. Chem. Soc., 2009, 131, 8756–8757 U. Pischel et al., J. Am. Chem. Soc., 2000, 122, 2027-2043
N HHOH
O
0.68 V
0.77 V
R X
Ru(bpy)3Cl2 (2.5 mol%)i-Pr2NEt / HCOOH (10 equiv.)
ori-Pr2NEt (2.0 equiv.) / Hantzsch ester (1.1 equiv.)
DMF, rt, 4-24hvisible light
R H
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
RX
R
N+
RH
H
NBoc
NCOOMe
COOMeH
H
95%
O N
Bn
O O
HPh
OH
95% from Br80% from Cl
I
O
OPh
HO
OPh
H
I O
OPh
H
88% from ClHantzsch ester
81% from ClHantzsch ester
89% from ClHantzsch ester
Reductive dehalogenation: activated halides
J. M. R. Narayanam, J. W. Tucker, C. R. J. Stephenson, J. Am. Chem. Soc., 2009, 131, 8756–8757 U. Pischel et al., J. Am. Chem. Soc., 2000, 122, 2027-2043
N HHOH
O
0.68 V
0.77 V
R X
Ru(bpy)3Cl2 (2.5 mol%)i-Pr2NEt / HCOOH (10 equiv.)
ori-Pr2NEt (2.0 equiv.) / Hantzsch ester (1.1 equiv.)
DMF, rt, 4-24hvisible light
R H
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
RX
R
N+
RH
H
NBoc
NCOOMe
COOMeH
H
95%
O N
Bn
O O
HPh
OH
95% from Br80% from Cl
I
O
OPh
HO
OPh
H
I O
OPh
H
88% from ClHantzsch ester
81% from ClHantzsch ester
89% from ClHantzsch ester
R X
Ir(ppy)3 (1.0−2.5 mol%)n-Bu3N (2−10 equiv.)
HCOOH (5−10 equiv.) or Hantzsch ester (1.1 equiv.)
DMF , 2.5−60hvisible light
R H
Reductive dehalogenation: unactivated iodides
J. D. Nguyen, E. M. D’Amato, J. M. R. Narayanam, C. R. J. Stephenson, Nature Chem., 2012, 4, 854–859
H
BnO 4
95%
N H5
85%
O
O
O
O
OH
H
MeOOC NH2
H83% 93%
Use of Ir(ppy)3: better reducing power E = -1.73 V
-1.59 V < E (iodobenzene) < -2.24 V
R X
Ir(ppy)3 (1.0−2.5 mol%)n-Bu3N (2−10 equiv.)
HCOOH (5−10 equiv.) or Hantzsch ester (1.1 equiv.)
DMF , 2.5−60hvisible light
R H
Reductive dehalogenation: unactivated iodides
J. D. Nguyen, E. M. D’Amato, J. M. R. Narayanam, C. R. J. Stephenson, Nature Chem., 2012, 4, 854–859
H
BnO 4
95%
N H5
85%
O
O
O
O
OH
H
MeOOC NH2
H83% 93%
Use of Ir(ppy)3: better reducing power E = -1.73 V
-1.59 V < E (iodobenzene) < -2.24 V
Reduction of hydrazides and hydrazines
M. Zhu, N. Zheng, Synthesis, 2011, 14, 2223-2236
Ru*(II)/Ru(I) = 1.45 V
RuII
N
N
NN
NNN
N
NN
NN
Ph N
OPh
NH2
N Ph
NH2
Ru(bpz)3(PF6)2 (2 mol%)
MeCN/MeOH, 24-48hair, visible light
Ph NH
OPh
NH
Ph
74%
83%
Ru(bpz)32+
*Ru(bpz)32+ Ru(bpz)3+
N NH2R
PhN NH2R
Ph
−H+N NHR
Ph
N NR
PhO O
H
N NR
PhO OH N NR
PhO
OH
NR
Ph
O2
NR
Ph
H+NR
Ph
H
Reduction of hydrazides and hydrazines
M. Zhu, N. Zheng, Synthesis, 2011, 14, 2223-2236
Ru*(II)/Ru(I) = 1.45 V
RuII
N
N
NN
NNN
N
NN
NN
Ph N
OPh
NH2
N Ph
NH2
Ru(bpz)3(PF6)2 (2 mol%)
MeCN/MeOH, 24-48hair, visible light
Ph NH
OPh
NH
Ph
74%
83%
Ru(bpz)32+
*Ru(bpz)32+ Ru(bpz)3+
N NH2R
PhN NH2R
Ph
−H+N NHR
Ph
N NR
PhO O
H
N NR
PhO OH N NR
PhO
OH
NR
Ph
O2
NR
Ph
H+NR
Ph
H
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
i-Pr2NEt
ArN3
ArN3 Ar
NN+N
H
ArNN+N
H
ArNH
H+
ArNH
H
i-Pr2NEt
NEt
i-Pr2NEt
Reduction of azides
Y. Chen, A. S. Kamlet, J. B. Steinman, D. R. Liu, Nature Chem., 2011, 3, 146-153
N3
R
Ru(bpy)3Cl2 (5 mol%)i-PrNEt2/HCOOH (10 equiv.)Hantzsch ester (1.5 equiv.)
CH2Cl2, rt, 2hvisible light
NH2
R
• Work in aqueous media, linked with DNA, sugars • Chemoselective: inert to halides, mesylates, aldehydes, free hydroxyl, carboxylic acids, amides, alkenes, alkynes
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
i-Pr2NEt
ArN3
ArN3 Ar
NN+N
H
ArNN+N
H
ArNH
H+
ArNH
H
i-Pr2NEt
NEt
i-Pr2NEt
Reduction of azides
Y. Chen, A. S. Kamlet, J. B. Steinman, D. R. Liu, Nature Chem., 2011, 3, 146-153
N3
R
Ru(bpy)3Cl2 (5 mol%)i-PrNEt2/HCOOH (10 equiv.)Hantzsch ester (1.5 equiv.)
CH2Cl2, rt, 2hvisible light
NH2
R
• Work in aqueous media, linked with DNA, sugars • Chemoselective: inert to halides, mesylates, aldehydes, free hydroxyl, carboxylic acids, amides, alkenes, alkynes
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
i-Pr2NEt
ArN3
ArN3 Ar
NN+N
H
ArNN+N
H
ArNH
H+
ArNH
H
i-Pr2NEt
NEt
i-Pr2NEt
Reduction of azides
Y. Chen, A. S. Kamlet, J. B. Steinman, D. R. Liu, Nature Chem., 2011, 3, 146-153
N3
R
Ru(bpy)3Cl2 (5 mol%)i-PrNEt2/HCOOH (10 equiv.)Hantzsch ester (1.5 equiv.)
CH2Cl2, rt, 2hvisible light
NH2
R
• Work in aqueous media, linked to DNA, sugars • Chemoselective: inert to halides, mesylates, aldehydes, free hydroxyl, carboxylic acids, amides, alkenes, alkynes
Deprotection of p-Methoxybenzylether
J. W. Tucker, J. M. R. Narayanam, P. S. Shah, C. R. J. Stephenson, Chem. Commun., 2011, 47, 5040-5042
IrIII
N
NN
N
tBu
tBu
F3C F
FCF3
FF
IrL33+
*IrL33+ IrL34+
CCl3BrCCl3
R O
OMe
R O
OMe
R O
OMeCHCl3
R OH
O
H
OMe
H
O O O H6
80%a
O H
84%
Bn O O H6O H
69%
BocHN O H6
79%a92%a
- 1.21 V 1.68 V
R O
OMe
Ir(dF(CF3)ppy)2(dtbbpy)PF6 (1 mol%)BrCCl3 (2.0 equiv.)
MeCN, 12-18hblue LEDs
R OH
Deprotection of p-Methoxybenzylether
J. W. Tucker, J. M. R. Narayanam, P. S. Shah, C. R. J. Stephenson, Chem. Commun., 2011, 47, 5040-5042
IrIII
N
NN
N
tBu
tBu
F3C F
FCF3
FF
IrL33+
*IrL33+ IrL34+
CCl3BrCCl3
R O
OMe
R O
OMe
R O
OMeCHCl3
R OH
O
H
OMe
H
O O O H6
80%a
O H
84%
Bn O O H6O H
69%
BocHN O H6
79%a92%a
- 1.21 V 1.68 V
R O
OMe
Ir(dF(CF3)ppy)2(dtbbpy)PF6 (1 mol%)BrCCl3 (2.0 equiv.)
MeCN, 12-18hblue LEDs
R OH
Deprotection of p-Methoxybenzylether
J. W. Tucker, J. M. R. Narayanam, P. S. Shah, C. R. J. Stephenson, Chem. Commun., 2011, 47, 5040-5042
IrIII
N
NN
N
tBu
tBu
F3C F
FCF3
FF
IrL33+
*IrL33+ IrL34+
CCl3BrCCl3
R O
OMe
R O
OMe
R O
OMeCHCl3
R OH
O
H
OMe
H
O O O H6
80%a
O H
84%
Bn O O H6O H
69%
BocHN O H6
79%a92%a
- 1.21 V 1.68 V
R O
OMe
Ir(dF(CF3)ppy)2(dtbbpy)PF6 (1 mol%)BrCCl3 (2.0 equiv.)
MeCN, 12-18hblue LEDs
R OH
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
O2 O2
N
OMe
COORAr
N
OMe
COORAr
OMe
Ar COOR
Br
Ar COOR Ar COOR
O Br HBr
O2 O2
Ar COOR
OO2
Ru(bpy)32+
air, baseRu(bpy)3+
Aerobic oxitation of benzylic halides
Y. Su, L. Zhang, N. Jiao, Org. Lett., 2011, 13, 2168-2171
Ar COOR
Br
Ru(bpy)3Cl2 (0.5 mol%)4-methoxypyridine (20 mol%)
Li2CO3 (1.0 equiv.)
DMA, 25°C, air, 24-48h Ar COOR
O
Ph COOEt
O
75%
Cl
COOiPr
O
75%
Ph
O
O
Cl
82%from Cl
Ph Ph
O
40%2.5 equiv. of pyridine
Cs2CO3
OO
O
0%
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
O2 O2
N
OMe
COORAr
N
OMe
COORAr
OMe
Ar COOR
Br
Ar COOR Ar COOR
O Br HBr
O2 O2
Ar COOR
OO2
Ru(bpy)32+
air, baseRu(bpy)3+
Aerobic oxitation of benzylic halides
Y. Su, L. Zhang, N. Jiao, Org. Lett., 2011, 13, 2168-2171
Ar COOR
Br
Ru(bpy)3Cl2 (0.5 mol%)4-methoxypyridine (20 mol%)
Li2CO3 (1.0 equiv.)
DMA, 25°C, air, 24-48h Ar COOR
O
Ph COOEt
O
75%
Cl
COOiPr
O
75%
Ph
O
O
Cl
82%from Cl
Ph Ph
O
40%2.5 equiv. of pyridine
Cs2CO3
OO
O
0%
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
O2 O2
N
OMe
COORAr
N
OMe
COORAr
OMe
Ar COOR
Br
Ar COOR Ar COOR
O Br HBr
O2 O2
Ar COOR
OO2
Ru(bpy)32+
air, baseRu(bpy)3+
Aerobic oxitation of benzylic halides
Y. Su, L. Zhang, N. Jiao, Org. Lett., 2011, 13, 2168-2171
Ar COOR
Br
Ru(bpy)3Cl2 (0.5 mol%)4-methoxypyridine (20 mol%)
Li2CO3 (1.0 equiv.)
DMA, 25°C, air, 24-48h Ar COOR
O
Ph COOEt
O
75%
Cl
COOiPr
O
75%
Ph
O
O
Cl
82%from Cl
Ph Ph
O
40%2.5 equiv. of pyridine
Cs2CO3
OO
O
0%
C-C Bond Formation
Reductive radical cyclization
J. W. Tucker, J. D. Nguyen, J. M. R. Narayanam, S. W. Krabbe, C. R. J. Stephenson, Chem. Commun, 2010, 46, 4985-4987
BrMeOOC COOMe Ru(bpy)3Cl2 (1 mol%)Et3N (2.0 equiv.)
DMF, blue LEDs69%
MeOOC COOMe
Br BrOH
Ir(ppy)2(dtbbpy)PF6(1 mol%)
OH
Br
85%
Br
NO
NO
73%
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
BrMeOOC COOMe
MeOOC COOMeCOOMe
MeOOC
COOMeMeOOC
COOMeMeOOC
Reductive radical cyclization
J. W. Tucker, J. D. Nguyen, J. M. R. Narayanam, S. W. Krabbe, C. R. J. Stephenson, Chem. Commun, 2010, 46, 4985-4987
BrMeOOC COOMe Ru(bpy)3Cl2 (1 mol%)Et3N (2.0 equiv.)
DMF, blue LEDs69%
MeOOC COOMe
Br BrOH
Ir(ppy)2(dtbbpy)PF6(1 mol%)
OH
Br
85%
Br
NO
NO
73%
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
BrMeOOC COOMe
MeOOC COOMeCOOMe
MeOOC
COOMeMeOOC
COOMeMeOOC
Br BrOH
Ir(ppy)2(dtbbpy)PF6(1 mol%)
OH
Br
85%
Br
NO
NO
73%
BrMeOOC COOMe Ru(bpy)3Cl2 (1 mol%)Et3N (2.0 equiv.)
DMF, blue LEDs69%
MeOOC COOMe
Reductive radical cyclization
J. W. Tucker, J. D. Nguyen, J. M. R. Narayanam, S. W. Krabbe, C. R. J. Stephenson, Chem. Commun, 2010, 46, 4985-4987
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)3+
N N
BrMeOOC COOMe
MeOOC COOMeCOOMe
MeOOC
COOMeMeOOC
COOMeMeOOC
Atom Transfer Radical Addition
J. W. Tucker, J. D. Nguyen, J. M. R. Narayanam, S. W. Krabbe, C. R. J. Stephenson, Chem. Commun, 2010, 46, 4985-4987
R X R' R''
Ru(bpy)3Cl2 (1.0 mol%)10 mol% LiBr
DMSO, visible light R'
R R''
X
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)33+
R X R X
R'R
R'
R'RLiX
R X
R'R
R'R
X
X
Radical-polar crossover
Radical propagation
NHBoc NHBocBr
EtO2C
EtO2C
BrEtO2CFF
CO2Et CO2Et
IF3C
99%
88%
90%
Atom Transfer Radical Addition
J. W. Tucker, J. D. Nguyen, J. M. R. Narayanam, S. W. Krabbe, C. R. J. Stephenson, Chem. Commun, 2010, 46, 4985-4987
R X R' R''
Ru(bpy)3Cl2 (1.0 mol%)10 mol% LiBr
DMSO, visible light R'
R R''
X
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)33+
R X R X
R'R
R'
R'RLiX
R X
R'R
R'R
X
X
Radical-polar crossover
Radical propagation
NHBoc NHBocBr
EtO2C
EtO2C
BrEtO2CFF
CO2Et CO2Et
IF3C
99%
88%
90%
Atom Transfer Radical Addition
J. W. Tucker, J. D. Nguyen, J. M. R. Narayanam, S. W. Krabbe, C. R. J. Stephenson, Chem. Commun, 2010, 46, 4985-4987
R X R' R''
Ru(bpy)3Cl2 (1.0 mol%)10 mol% LiBr
DMSO, visible light R'
R R''
X
Ru(bpy)32+
*Ru(bpy)32+ Ru(bpy)33+
R X R X
R'R
R'
R'RLiX
R X
R'R
R'R
X
X
Radical-polar crossover
Radical propagation
NHBoc NHBocBr
EtO2C
EtO2C
BrEtO2CFF
CO2Et CO2Et
IF3C
99%
88%
90%
α-Amino C-H arylation
Nn
RX
CN
EWG
Ir(ppy)3 (1 mol%)NaOAc (2.0 equiv.)
DMA, 23°C, 12hvisible light (26W CFL)
Nn
R
XEWG
Nn
RIr(ppy)3
*Ir(ppy)3 Ir(ppy)3+
XEWG CN
XEWG CN
Nn
R
NaOAcN
n
R
Nn
R
XEWG
NC
−CN−
Nn
R
XEWG
NPh CN
N
BocN
Ph CN
NBn
CNN
N
Ph
NN
Ph NHNPh
N
S
NO
F
N OO
NHAc
ON
94% 95%
90% (6.7:1 r.r.) 72%
61% 79%
58%A. McNally, C. K. Prier, D. W. C. MacMillan, Science, 2011, 334, 1114-1117
α-Amino C-H arylation
Nn
RX
CN
EWG
Ir(ppy)3 (1 mol%)NaOAc (2.0 equiv.)
DMA, 23°C, 12hvisible light (26W CFL)
Nn
R
XEWG
Nn
RIr(ppy)3
*Ir(ppy)3 Ir(ppy)3+
XEWG CN
XEWG CN
Nn
R
NaOAcN
n
R
Nn
R
XEWG
NC
−CN−
Nn
R
XEWG
NPh CN
N
BocN
Ph CN
NBn
CNN
N
Ph
NN
Ph NHNPh
N
S
NO
F
N OO
NHAc
ON
94% 95%
90% (6.7:1 r.r.) 72%
61% 79%
58%A. McNally, C. K. Prier, D. W. C. MacMillan, Science, 2011, 334, 1114-1117
α-Amino C-H arylation
Nn
RX
CN
EWG
Ir(ppy)3 (1 mol%)NaOAc (2.0 equiv.)
DMA, 23°C, 12hvisible light (26W CFL)
Nn
R
XEWG
Nn
RIr(ppy)3
*Ir(ppy)3 Ir(ppy)3+
XEWG CN
XEWG CN
Nn
R
NaOAcN
n
R
Nn
R
XEWG
NC
−CN−
Nn
R
XEWG
NPh CN
N
BocN
Ph CN
NBn
CNN
N
Ph
NN
Ph NHNPh
N
S
NO
F
N OO
NHAc
ON
94% 95%
90% (6.7:1 r.r.) 72%
61% 79%
58%A. McNally, C. K. Prier, D. W. C. MacMillan, Science, 2011, 334, 1114-1117
Trifluoromethylation of Arenes via Direct C-H functionalization
D. A. Nagib, D. W. C. MacMillan, Nature, 2011, 480, 224-228
R
CF3SO2Cl2 (1-4 equiv.)Photocatalyst (1-2 mol%)
K2HPO4, MeCN, 23°Cvisible light
A
C
B
Y
X
RA
C
B
Y
X
CF3
CF3
CF3
R
Ru(phen)32+
*Ru(phen)32+ Ru(phen)33+
S ClF3CO
OS ClF3CO
O
SO2Cl-
CF3
RCF3
CF3H
−H+ CF3R R
N
N
N
N
NH O
N
S
CF3 CF3 CF3
OMe
CF3
OMe
O CF3
CF3
CF3
CF3 Me3Si
OMe
CF3
88% 80% 70%
82% 78% 87%
70% 74% 76%
N OH
OOHOHO
NH
F
4-CF3-Lipitor27%
2-CF3-Lipitor25%
4'-CF3-Lipitor22%
Trifluoromethylation of Arenes via Direct C-H functionalization
D. A. Nagib, D. W. C. MacMillan, Nature, 2011, 480, 224-228
R
CF3SO2Cl2 (1-4 equiv.)Photocatalyst (1-2 mol%)
K2HPO4, MeCN, 23°Cvisible light
A
C
B
Y
X
RA
C
B
Y
X
CF3
CF3
CF3
R
Ru(phen)32+
*Ru(phen)32+ Ru(phen)33+
S ClF3CO
OS ClF3CO
O
SO2Cl-
CF3
RCF3
CF3H
−H+ CF3R R
N
N
N
N
NH O
N
S
CF3 CF3 CF3
OMe
CF3
OMe
O CF3
CF3
CF3
CF3 Me3Si
OMe
CF3
88% 80% 70%
82% 78% 87%
70% 74% 76%
N OH
OOHOHO
NH
F
4-CF3-Lipitor27%
2-CF3-Lipitor25%
4'-CF3-Lipitor22%
Trifluoromethylation of Arenes via Direct C-H functionalization
D. A. Nagib, D. W. C. MacMillan, Nature, 2011, 480, 224-228
R
CF3SO2Cl2 (1-4 equiv.)Photocatalyst (1-2 mol%)
K2HPO4, MeCN, 23°Cvisible light
A
C
B
Y
X
RA
C
B
Y
X
CF3
CF3
CF3
R
Ru(phen)32+
*Ru(phen)32+ Ru(phen)33+
S ClF3CO
OS ClF3CO
O
SO2Cl-
CF3
RCF3
CF3H
−H+ CF3R R
N
N
N
N
NH O
N
S
CF3 CF3 CF3
OMe
CF3
OMe
O CF3
CF3
CF3
CF3 Me3Si
OMe
CF3
88% 80% 70%
82% 78% 87%
70% 74% 76%
N OH
OOHOHO
NH
F
4-CF3-Lipitor27%
2-CF3-Lipitor25%
4'-CF3-Lipitor22%
Trifluoromethylation of Arenes via Direct C-H functionalization
D. A. Nagib, D. W. C. MacMillan, Nature, 2011, 480, 224-228
R
CF3SO2Cl2 (1-4 equiv.)Photocatalyst (1-2 mol%)
K2HPO4, MeCN, 23°Cvisible light
A
C
B
Y
X
RA
C
B
Y
X
CF3
CF3
CF3
R
Ru(phen)32+
*Ru(phen)32+ Ru(phen)33+
S ClF3CO
OS ClF3CO
O
SO2Cl-
CF3
RCF3
CF3H
−H+ CF3R R
N
N
N
N
NH O
N
S
CF3 CF3 CF3
OMe
CF3
OMe
O CF3
CF3
CF3
CF3 Me3Si
OMe
CF3
88% 80% 70%
82% 78% 87%
70% 74% 76%
N OH
OOHOHO
NH
F
4-CF3-Lipitor27%
2-CF3-Lipitor25%
4'-CF3-Lipitor22%
Ru(bpy)32+
*Ru(bpy)32+
Ru(bpy)3+
N
N
MeO
MetBu
Y
FG
N
N+
MeO
MetBu
Y
FGBrFG
FG
O
HY
FG
N
NH
MeO
MetBu
O
HY
N
N
MeO
MetBu
Y
FG
PHOTOREDOX ORGANOCATALYSIS
Merging Photoredox and Organocatalysis: Enantioselective α-Alkylation of Aldehydes
D. A. Nicewicz, D. W. C. MacMillan, Science, 2008, 322, 77-80
H
OY FG Br
R
Ru(bpy)3Cl2 (0.5 mol%)organocatalyst (20 mol%)
2,6-lutidine (2.0 equiv.)
DMF, 23°Cvisible light2.0 equiv.
H
O
YFG
R
H
O
Et
COOEt
COOEt
86%, 90% ee
H
O
COOEt
COOEt
NBoc
66%, 91% ee
H
O
COOEt
COOEt
H
O
Hex
84%, 95% ee
O
NO2
H
O
HexCOOEt
80%, 88% ee
COOEt
H
O
Hex
OCH2CF3
O
80%, 92% ee
Ph
92%, 90% ee
Ru(bpy)32+
*Ru(bpy)32+
Ru(bpy)3+
N
N
MeO
MetBu
Y
FG
N
N+
MeO
MetBu
Y
FGBrFG
FG
O
HY
FG
N
NH
MeO
MetBu
O
HY
N
N
MeO
MetBu
Y
FG
PHOTOREDOX ORGANOCATALYSIS
Merging Photoredox and Organocatalysis: Enantioselective α-Alkylation of Aldehydes
D. A. Nicewicz, D. W. C. MacMillan, Science, 2008, 322, 77-80
H
OY FG Br
R
Ru(bpy)3Cl2 (0.5 mol%)organocatalyst (20 mol%)
2,6-lutidine (2.0 equiv.)
DMF, 23°Cvisible light2.0 equiv.
H
O
YFG
R
H
O
Et
COOEt
COOEt
86%, 90% ee
H
O
COOEt
COOEt
NBoc
66%, 91% ee
H
O
COOEt
COOEt
H
O
Hex
84%, 95% ee
O
NO2
H
O
HexCOOEt
80%, 88% ee
COOEt
H
O
Hex
OCH2CF3
O
80%, 92% ee
Ph
92%, 90% ee
Ru(bpy)32+
*Ru(bpy)32+
Ru(bpy)3+
N
N
MeO
MetBu
Y
FG
N
N+
MeO
MetBu
Y
FGBrFG
FG
O
HY
FG
N
NH
MeO
MetBu
O
HY
N
N
MeO
MetBu
Y
FG
PHOTOREDOX ORGANOCATALYSIS
Merging Photoredox and Organocatalysis: Enantioselective α-Alkylation of Aldehydes
D. A. Nicewicz, D. W. C. MacMillan, Science, 2008, 322, 77-80
H
OY FG Br
R
Ru(bpy)3Cl2 (0.5 mol%)organocatalyst (20 mol%)
2,6-lutidine (2.0 equiv.)
DMF, 23°Cvisible light2.0 equiv.
H
O
YFG
R
H
O
Et
COOEt
COOEt
86%, 90% ee
H
O
COOEt
COOEt
NBoc
66%, 91% ee
H
O
COOEt
COOEt
H
O
Hex
84%, 95% ee
O
NO2
H
O
HexCOOEt
80%, 88% ee
COOEt
H
O
Hex
OCH2CF3
O
80%, 92% ee
Ph
92%, 90% ee
Ru(bpy)32+
*Ru(bpy)32+
Ru(bpy)3+
O
H R
O
HY
PHOTOREDOX ORGANOCATALYSIS
CN
CN
CN
CN
NR
NH
NR
NR
−H+
NR
CN
CN
CN
H2O, −CN−
β-Arylation of Aldehydes and Ketones
M. T. Pirnot, D. A. Rankic, D. B. C. Martin, D. W. C. MacMillan, Science, 2013, 339, 1593-1596
H
OIr(ppy)3 (1.0 mol%)
organocatalyst (20 mol%)DABCO, AcOH
H2O, DMPU, 23°Cvisible light
H
O
R X
CN
EWG
R
X
EWG
NH
HN
H
O
NC
63%
H
O
NBoc
CN
71%
H
O Pent
N
70%
O
tBu CN
70%>20:1 drazepane
O
O
CN
63%piperidine
O
CN82%
55% eecinchona derived
catalyst
Ru(bpy)32+
*Ru(bpy)32+
Ru(bpy)3+
O
H R
O
HY
PHOTOREDOX ORGANOCATALYSIS
CN
CN
CN
CN
NR
NH
NR
NR
−H+
NR
CN
CN
CN
H2O, −CN−
β-Arylation of Aldehydes and Ketones
M. T. Pirnot, D. A. Rankic, D. B. C. Martin, D. W. C. MacMillan, Science, 2013, 339, 1593-1596
H
OIr(ppy)3 (1.0 mol%)
organocatalyst (20 mol%)DABCO, AcOH
H2O, DMPU, 23°Cvisible light
H
O
R X
CN
EWG
R
X
EWG
NH
HN
H
O
NC
63%
H
O
NBoc
CN
71%
H
O Pent
N
70%
O
tBu CN
70%>20:1 drazepane
O
O
CN
63%piperidine
O
CN82%
55% eecinchona derived
catalyst
Ru(bpy)32+
*Ru(bpy)32+
Ru(bpy)3+
O
H R
O
HY
PHOTOREDOX ORGANOCATALYSIS
CN
CN
CN
CN
NR
NH
NR
NR
−H+
NR
CN
CN
CN
H2O, −CN−
β-Arylation of Aldehydes and Ketones
M. T. Pirnot, D. A. Rankic, D. B. C. Martin, D. W. C. MacMillan, Science, 2013, 339, 1593-1596
H
OIr(ppy)3 (1.0 mol%)
organocatalyst (20 mol%)DABCO, AcOH
H2O, DMPU, 23°Cvisible light
H
O
R X
CN
EWG
R
X
EWG
NH
HN
H
O
NC
63%
H
O
NBoc
CN
71%
H
O Pent
N
70%
O
tBu CN
70%>20:1 drazepane
O
O
CN
63%piperidine
O
CN82%
55% eecinchona derived
catalyst
Merging Photoredox and TM catalysis: Coupling of α-carboxyl sp3 carbon with Aryl Halides
Z. Zuo, D. T. Ahneman, L. Chu, J. A. Terrett, A. G. Doyle, D. W. C. MacMillan, Science, 2014, 345, 437-440
NCOOH
R
X
Ir[dF(CF3)ppy]2(dtbbpy)PF6 (1 mol%)NiCl2.glyme (10 mol%)
dtbbpy (15 mol%)
Cs2CO3 (1.5 equiv.), DMF, 48-72 hblue LEDs
NRR
R
1.21 V
0.95 V
-1.2 V
PHOTOREDOX*IrIII
IrIII
IrII LnNiIX
LnNi0LnArNiIIX
NiIIILnAlkX
ArN
COOH
Boc
NBoc
NBoc
XR
NBoc
R
TM
LnNiIIX2
SubstrateIrIII
−H+
−CO2
-1.37 V
-1.7 V
NBoc
OMe
78%from ArI
NBoc
CN
75%from ArBr
NBoc
NF
78%from ArCl
F
N
O
Boc Ac61%
from ArBr
NHBoc
Ac
72%from ArBr
N
NHBoc
AcBoc83%
from ArBr
MeS
NHBoc
AcO
Ac
83%from ArBr
82%from ArBr
N
84%from ArBr
anddimethylaniline
Merging Photoredox and TM catalysis: Coupling of α-carboxyl sp3 carbon with Aryl Halides
Z. Zuo, D. T. Ahneman, L. Chu, J. A. Terrett, A. G. Doyle, D. W. C. MacMillan, Science, 2014, 345, 437-440
NCOOH
R
X
Ir[dF(CF3)ppy]2(dtbbpy)PF6 (1 mol%)NiCl2.glyme (10 mol%)
dtbbpy (15 mol%)
Cs2CO3 (1.5 equiv.), DMF, 48-72 hblue LEDs
NRR
R
1.21 V
0.95 V
-1.2 V
PHOTOREDOX*IrIII
IrIII
IrII LnNiIX
LnNi0LnArNiIIX
NiIIILnAlkX
ArN
COOH
Boc
NBoc
NBoc
XR
NBoc
R
TM
LnNiIIX2
SubstrateIrIII
−H+
−CO2
-1.37 V
-1.7 V
NBoc
OMe
78%from ArI
NBoc
CN
75%from ArBr
NBoc
NF
78%from ArCl
F
N
O
Boc Ac61%
from ArBr
NHBoc
Ac
72%from ArBr
N
NHBoc
AcBoc83%
from ArBr
MeS
NHBoc
AcO
Ac
83%from ArBr
82%from ArBr
N
84%from ArBr
anddimethylaniline
Merging Photoredox and TM catalysis: Coupling of α-carboxyl sp3 carbon with Aryl Halides
Z. Zuo, D. T. Ahneman, L. Chu, J. A. Terrett, A. G. Doyle, D. W. C. MacMillan, Science, 2014, 345, 437-440
NCOOH
R
X
Ir[dF(CF3)ppy]2(dtbbpy)PF6 (1 mol%)NiCl2.glyme (10 mol%)
dtbbpy (15 mol%)
Cs2CO3 (1.5 equiv.), DMF, 48-72 hblue LEDs
NRR
R
1.21 V
0.95 V
-1.2 V
PHOTOREDOX*IrIII
IrIII
IrII LnNiIX
LnNi0LnArNiIIX
NiIIILnAlkX
ArN
COOH
Boc
NBoc
NBoc
XR
NBoc
R
TM
LnNiIIX2
SubstrateIrIII
−H+
−CO2
-1.37 V
-1.7 V
NBoc
OMe
78%from ArI
NBoc
CN
75%from ArBr
NBoc
NF
78%from ArCl
F
N
O
Boc Ac61%
from ArBr
NHBoc
Ac
72%from ArBr
N
NHBoc
AcBoc83%
from ArBr
MeS
NHBoc
AcO
Ac
83%from ArBr
82%from ArBr
N
84%from ArBr
anddimethylaniline
Enantioselective Coupling of α-carboxyl sp3 carbon with Aryl Halides
Z. Zuo, H. Cong, W. Li, J. Choi, G. C. Fu, D. W. C. MacMillan, J. Am. Chem. Soc., 2016, 138, 1832-1835
Photoredox-Assisted Suzuki-type Cross Coupling
J. C. Tellis, D. N. Primer, G. A. Molander, Science, 2014, 345, 433-436
Photoredox-Assisted Suzuki-type Cross Coupling
J. C. Tellis, D. N. Primer, G. A. Molander, Science, 2014, 345, 433-436
Photoredox-Assisted Suzuki-type Cross Coupling
J. C. Tellis, D. N. Primer, G. A. Molander, Science, 2014, 345, 433-436
Photoredox-Assisted Suzuki-type Cross Coupling
J. C. Tellis, D. N. Primer, G. A. Molander, Science, 2014, 345, 433-436
Photoredox-Assisted Hiyama-type Cross Coupling
M. Jouffroy, D. N. Primer, G. A. Molander, J. Am. Chem. Soc., 2016, 138, 475-478
Dual Photoredox and TM
MacMillan, Angew. Chem. Int. Ed., 2015, 54, 7929–7933
MacMillan, Nature, 2015, 524, 330–334
Glorius, J. Am. Chem. Soc., 2013, 135, 5505–5508
Sanford, J. Am. Chem. Soc., 2011, 133,18566–18569
Conclusions
Extremely versitile CC, CN, CO, CP, CB bond formation, FGI… [2+2], [4+2] cycloadditions, oxidative & reductive couplings…
Mild conditions
Room temperature Stable/commercial reagents
Combination with other types of catalysis
Organocatalysis, TM catalysis, HAT Rational design
Catalyst Reaction
Types of catalysts
Cu, Fe, W, … Metal-free: organic dyes
« Organic Photoredox Chemistry » N. A. Romero and D. A. Nicewicz, Chem. Rev., 2016, 16, 10075−10166
Conclusions
Extremely versitile CC, CN, CO, CP, CB bond formation, FGI… [2+2], [4+2] cycloadditions, oxidative & reductive couplings…
Mild conditions
Room temperature Stable/commercial reagents
Combination with other types of catalysis
Organocatalysis, TM catalysis, HAT Rational design
Catalyst Reaction
Types of catalysts
Cu, Fe, W, … Metal-free: organic dyes
« Organic Photoredox Chemistry » N. A. Romero and D. A. Nicewicz, Chem. Rev., 2016, 16, 10075−10166
Conclusions
Extremely versitile CC, CN, CO, CP, CB bond formation, FGI… [2+2], [4+2] cycloadditions, oxidative & reductive couplings…
Mild conditions
Room temperature Stable/commercial reagents
Combination with other types of catalysis
Organocatalysis, TM catalysis, HAT Rational design
Catalyst Reaction
Types of catalysts
Cu, Fe, W, … Metal-free: organic dyes
« Organic Photoredox Chemistry » N. A. Romero and D. A. Nicewicz, Chem. Rev., 2016, 16, 10075−10166
Conclusions
Extremely versitile CC, CN, CO, CP, CB bond formation, FGI… [2+2], [4+2] cycloadditions, oxidative & reductive couplings…
Mild conditions
Room temperature Stable/commercial reagents
Combination with other types of catalysis
Organocatalysis, TM catalysis, HAT Rational design
Catalyst Reaction
Types of catalysts
Cu, Fe, W, … Metal-free: organic dyes
« Organic Photoredox Chemistry » N. A. Romero and D. A. Nicewicz, Chem. Rev., 2016, 16, 10075−10166
Conclusions
Extremely versitile CC, CN, CO, CP, CB bond formation, FGI… [2+2], [4+2] cycloadditions, oxidative & reductive couplings…
Mild conditions
Room temperature Stable/commercial reagents
Combination with other types of catalysis
Organocatalysis, TM catalysis, HAT Rational design
Catalyst Reaction
Types of catalysts
Cu, Fe, W, … Metal-free: organic dyes
« Organic Photoredox Chemistry » N. A. Romero and D. A. Nicewicz, Chem. Rev., 2016, 16, 10075−10166
Conclusions
Extremely versitile CC, CN, CO, CP, CB bond formation, FGI… [2+2], [4+2] cycloadditions, oxidative & reductive couplings…
Mild conditions
Room temperature Stable/commercial reagents
Combination with other types of catalysis
Organocatalysis, TM catalysis, HAT Rational design
Catalyst Reaction
Types of catalysts
Cu, Fe, W, … Metal-free: organic dyes
« Organic Photoredox Chemistry » N. A. Romero and D. A. Nicewicz, Chem. Rev., 2016, 16, 10075−10166
