ripon college research group presentation

Investigating Substrate

Reactivity in Hydroacylation

Reactions with Rhodium

Catalysts

Geno Schneider

Dr. Joe Scanlon

Ripon College

Outline Background

Hydroacylation

Previous Studies

Chirality

Potential Energy Surfaces

Results

Conclusions

Ongoing and Future Research

Acknowledgments

References

Hydroacylation Alkene and aldehyde react to form a new carbon-

carbon bond

Intramolecular hydroacylation requires a catalyst

Previous Research Stanley Group at Iowa State

Found unique substitution effects and high

enantioselectivity

Previous Research Tested many substituents and ligands

Found as a backbone in narcotics

Previous Research Dr Sargent et. al

Computational Study on simple system

Brian Schumacher and Dr. Joe Scanlon

computationally studied Dr. Stanley's system

Mechanism Changes from Sargent

Additional Intermediate found

Chirality

Potential Energy Surfaces Depict relative energies

Reaction alternates between intermediates(local

minima) and transition states(local maxima).

Determine mechanisms of reactions

-65

-55

-45

-35

-25

-15

-5

De

lta

H (

kcal

/mo

l)

Reaction Coordinate

PES

Mechanism

Dr. Sargent Recreated Sargent’s system with two methods

H-coordination Intermediate was found in both cases

0

10

20

30

De

lta

E (k

cal/

mo

l)

Reaction Coordinate

PES

M06L

B3LYP

Sargent

6-HcoordTS

I6

Hcoord

Hcoord-7aTS

I7a

Sargent’s

TS

Enantioselective Reaction Intramolecular Hydroacylation catalyzed by

[Rh(BINAP)]

Enantioselectivity

Different side of alkene coordinating to Rh, allowing for R or S

enantiomers to be formed.

Pathway of R vs S Enantiomers

O

R1

R2

H

O

R1 R2

LRh(I)

H

H

R1 R2

LRh(I)

OO

R1 R2

LRh(I)

H

O

H

R2

LRh(I)

R1

O

H

R2

LRh(I)

R1

O

H

R2

R1

O

H

R2

R1

O

R1

R2

H

O

R1 R2

LRh(I)

H

H

R1 R2

LRh(I)

OO

R1 R2

LRh(I)

H

O

H

R2

LRh(I)

R1

O

H

R2

LRh(I)

R1

O

H

R2

R1

O

H

R2

R1

R Enantiomer S Enantiomer

-65

-55

-45

-35

-25

-15

-5

5

De

lta

H (

kcal

/mo

l)

Reaction Coordinate

PES

S Enantiomer

R Enantiomer

I2

SM

I1

TS1

I3

TS2

TS3

I4

TS4

I5

TS5

ΔH kcal/mol

TS1 TS2 TS3 TS4 TS5

R-S 2.9 11.1 -3.1 -0.5 3.0

3.90A

2.52A

S Enantiomer, Transition State 2

2.13A2.70A

R Enantiomer, Transition State 2

Distance to catalyst phenol rings

S Enantiomer, Transition State 2

Dihedral Angle=6.65

R Enantiomer, Transition State 2

Dihedral Angle= -16.40

Dihedral angle

Cyclopentene and

Cyclohexene

-25

-15

-5

5D

elt

a H

(kc

al/m

ol)

Reaction Coordinate

PES

Cyclohexane

Cyclopentane

I2

SM

I1

TS1

I3

TS2

TS3

I4

TS4

I5

TS5

ΔH kcal/mol

TS1 TS2 TS3 TS4 TS5

CH-CP 1.7 1.4 4.1 NA -7.2

Future Work Finish Cyclopentene pathway.

Analyze geometry to explain differences in energy.

Acknowledgements MU3C Cluster

National Science Foundation

Knop Scholarship Fund

Ripon College Chemistry Department

Dr. Joe Scanlon

References1. Beletskiy, E. V.; Sudheer, Ch.; Douglas, C. J. Cooperative Catalysis Approach to

Intramolecular Hydroacylation. J. Org. Chem, 2012, 77, 5884-5893.

2. Ghosh, A.; Stanley, L. M. Enantioselective hydroacylation of N-vinylindole-2-

carboxaldehydes. Chemical Communication 2014, 50, 2765-2768.

3. Dempsey Hyatt, I. F.; Anderson, H. K.; Morehead, Jr. A. T.; Sargent, A. L. Mechanism of

Rhodium-Catalyzed Intromolecular Hydroacylation: A Computational Study. Organometallics

2007, 27, 135-147.

4. Pawley, R. J.; Huertos, M. A.; Lloyd-Jones, G. C.; Weller, A. S.; Willis, M. C. Intermolecular

Alkyne Hydroacylation. Mechanistic Insight from the Isolation of the Vinyl Intermediate That

Precedes Reductive Elimination. Organometallics 2012, 31, 5650-5659.

5. Gao, J.; Wang, F.; Meng, Q.; Li, M. Density Functional Computations of Rh(I)-Catalyzed

Hydroacylation of Ethene or Ethyne. Journal of Theoretical and Computational Chemistry,

2008, 7, 1041-1053.