1. O
H NaOH Br 2.
Claisen Rearrangement
O
or
A A
HO M O
*
200
OH
* Pericyclic Reaction
A S
LUMO
LUM O
13C
=*
O
LUM O
keto intermediate not stable
H
*
Cyclic flow fl of electrons Concerted
A S
HOMO
HO M O
S
LU M O
S
Diels Alder
S
HO M O
Diels Alder Pericyclic Reaction
4 + 2 3 + 3
Diels Alder Pericyclic Reaction
Cope Pericyclic Reaction
A
B
Cope Rearrangement
O
Claisen Pericyclic Reaction
O
O
H
O O
O
H
O O
O
+ CO2
How do you recognize a Cope Reaction?
1 23 4 5 2 1 5 3 4
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Cope heat
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Cope
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Number the bonds Is it a 1-5 diene? diene?
Assess relative stability
A
B
C
D
E
The following compound undergoes a rearrangement.
N Cope
The following compound undergoes a rearrangement.
N N N
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Cope
Predict the product.
N N N
Predict the product.
N N N
A D
B E
C F
A D
B E
C F
N
N
N
N
N
N
The following compound undergoes a rearrangement.
Bullvalene
*
Cope
*
Predict the product.
Cope
J.Chem.Ed Link
A
B
C
D
E
Bullvalene
1 2 4 3
Bullvalene
This is molecule confused. This molecule is a fluxional molecule.
J.Chem.Ed Link
Cope
Oxy-Cope
HO HO
Driving force is carbonyl formation
O
Oxy-Cope
OH Cope H OH O
Cope
HO
O
OH O
A
B
C
D
Oxy-Cope
HO OH Cope H OH O
Cope
HO
HO
E
H CH3 HO H CH3 CH3 CH3
HO
Chairlike Transition state
O
A
H
B
CH3 O
H
HO
H
H
CH3
C
O
H
HO
D
O
H
CH3
CH3
H
H
H
H
O
H 1. NaOH Br 2.
Claisen Rearrangement
O
O
Claisen Rearrangement
1. base 2. CH3I O C H3 H+ O
*
200
OH
*
+
Claisen Heat
14C
=*
O
Pericyclic Reaction * H Cyclic flow of electrons Concerted
OH
O
Redraw O
keto intermediate "not s table"
Claisen O
Cope
Citral
Claisen O
Cope
O
Citral
redraw Claisen
O O
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Cope
redraw Claisen
O O
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Cope
O
What is the Claisen product?
O O O
What is the Cope product (Citral)?
O H O H O
A C
H
B
O H
A
B
O
C
D
D
O O
M e3 S i
O
M e3 S i O
O O
O
SiMe3
O
SiMe3
1. LD A 2. M e3 S iC l
1. LD A 2. M e 3 S iC l
O
heat
heat
H 2O O HO O O
F-
O
A
O O
B D
C