p. 445
Chapter 12: Organohalides
12.5 – 12.15 : Substitution and Elimination Reactions12.4 : The Grignard Reagent12.1-12.3 : Preparation of Alkyl Halides
Fig. 12-2, p. 455
The Walden Inversion Cycle (1896)
(+)-Maleic Acid[]D = +2.3
(-)-Maleic Acid[]D = -2.3
(+)-chlorosuccinic acid
(-)-chlorosuccinic acid
Fig. 12-5, p. 459
http://www.chemtube3d.com/Main%20Page.html
Characteristics of the SN2 reaction
1.Rate equation
Characteristics of the SN2 reaction
1.Rate equation
2.Molecular factors effecting SN2 reaction rate
Fig. 12-6, p. 460
The Effect of Reactant and Transition Structure Energies on Reaction Rate
p. 461
Effect of ELECTROPHILIC CARBON on SN2 rate
Fig. 12-7, p. 461
Effect of ELECTROPHILIC CARBON on SN2 rate
The sterics around the electrophilic carbon alters the SN2 rate by changing…
0%
0% A. The ground state energy of the starting materials.
B. The energy of the transition state.
Effect of ELECTROPHILIC CARBONon SN2 rate
p. 463
Effect of LEAVING GROUP on SN2 rate
The leaving group alters the SN2 rate by changing…
0%
0% A. The ground state energy of the starting materials.
B. The energy of the transition state.
Effect of LEAVING GROUP on SN2 rate
Table 12-2, p. 462
Effect of NUCLEOPHILE on SN2 rate
The nucleophile alters the SN2 rate by changing…
52%
48% A. The ground state energy of the starting materials.
B. The energy of the transition state.
Effect of NUCLEOPHILE on SN2 rate
p. 465
Effect of Solvent on SN2 rate
Poorly solvated anion(increased nucleophilicity)
O
CNH
CH3
CH3
+
-
OC
N
H
CH3
H3C
O
CN H
H3C
CH3
O CN
H
H3C
CH3
++
+-
-
-X-
Well solvated anion(reduced nucleophilicity)
The solvent alters the SN2 rate by changing…
20%
80% A. The ground state energy of the starting materials.
B. The energy of the transition state.
O
CNH
CH3
CH3
+
-
OC
N
H
CH3
H3C
O
CN H
H3C
CH3
O CN
H
H3C
CH3
++
+-
-
-X-
Solvent effects on SN2 rate
Fig. 12-8, p. 466
Characteristics of the SN1 reaction
1.Rate equation
Characteristics of the SN1 reaction
1.Rate equation
2.Molecular factors effecting SN1 reaction rate
p. 467
Effect of electrophilic carbon on SN1 rate
Fig. 12-11, p. 469
Stereochemical effects of the SN1 mechanism
Fig. 12-12, p. 470
Stereochemical effects of the SN1 mechanism
p. 472
Effect of electrophilic carbon on SN1 rate:
Carbocation Stability
Fig. 12-13, p. 471
Effect of electrophilic carbon on SN1 rate:
Resonance in Carbocations
p. 472
Bond Disassociation Energies and Carbocation Stability
<
p. 472
Effect of LEAVING GROUP on SN2 rate
Effect of LEAVING GROUP on SN1 rate
Fig. 12-15, p. 474
Effect of Solvent on SN1 rate
p. 474
Effect of Solvent on SN1 rate
SN2 vs. SN1
What is the mechanism for the reaction below?
50%
50% A. SN1
B. SN2
Cl NaI
DMF
I
What is the mechanism for the reaction below?
50%
50% A. SN1
B. SN2
CH3
OHCH3
ClHClH2O
What is the mechanism for the reaction below?
50%
50% A. SN1
B. SN2
OHHBr
BrCH3CO2H
What is the mechanism for the reaction below?
50%
50% A. SN1
B. SN2
BrCH3ONa
OCH3CH3OH
Elimination Reactions
1.Intro: Eliminations vs. Substitutions
The E2 Mechanism
1.Rate
2.Molecular factors effecting the E2 mechanism
Stereochemistry
Zaitzev’s Rule
Barton’s Experiments
Fig. 12-19, p. 482
Stereochemistry of the E2 mechanism
Elimination Reactions : The E1 Mechanism
1.Rate
2.E1 and SN1
3.Molecular factors effecting the E2 mechanism
Stereochemistry
Zaitzev’s Rule
Summing it all up : SN1, SN2, E1 and E2
1. Primary Alkyl Halides
2. Secondary Alkyl Halide
3. Tertiary Alkyl Halides
Table 12-1, p. 446
Properties of Alkyl Halides
p. 447
Properties of Alkyl Halides
p. 453
The Grignard Reagent
p. 227
Synthesis of alkyl halides : review1. Addition of HX to an alkene (section 7.6)
a. Obeys Markovnikov’s Rule (section 7.7)
p. 239
Synthesis of alkyl halides : review1. Addition of HX to an alkene (section 7.6)
a. Obeys Markovnikov’s Rule (section 7.7)b. Carbocations that can rearrange, will rearrange (section 7.10)
p. 255
Synthesis of alkyl halides : review2. Addition of X2 to an alkene (section 8.2)
Anti addition
p. 255
Synthesis of alkyl halides : review3. Radical Halogenation (section 6.3)
CH3
CC
CH3
HH
H H
+Cl2
CH3
CC
H2C
HH
H HClCH3
CC
CH3
HH
H Clheator
light
Statistical
Synthesis of alkyl halides : New
1. From alkynes
Allylic bromination with N-Bromo
Succinimide
2. From Alcohols
a. Using strong acid
b. Via Tosylates
c. Using SOCl2 and PBr3
N
O
O
Br
Fig. 12-1, p. 449
The Allyl Radical
End