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904 CHAPTER 21 
 
 
21.113. Options (c) and (d) are enols, not enolates, so 
they can be ruled out. The base (diisopropylamide) is 
sterically hindered, so we expect formation of the less 
substituted (kinetic) enolate, which corresponds with 
option (b). 
 
 
 
21.114. The product is an ,-unsaturated ketone: 
 
 
 
Therefore, it can be prepared via an aldol condensation, 
using the following starting materials: 
 
 
 
These compounds correspond with option (c). 
 
 
21.115. This process involves the installation of two 
alkyl groups bear a carbonyl group: an ethyl group at the 
alpha position and a methyl group at the beta position. 
This can be achieved by first installing the methyl group 
at the beta position, by treating the starting compound 
with Me2CuLi, to give an enolate, followed by alkylation 
with ethyl iodide to give the desired product: 
 
 
Therefore, the answer is (d).
 
 
 
21.116. 
(a) Under strongly basic conditions, an enolate is formed. Then, under these conditions, an elimination-addition 
reaction can occur (Section 18.14), in which the nucleophilic enolate attacks the tethered benzyne in a ring-forming 
reaction, followed by protonation. 
 
N
O
OR
Br
H
Y
H2N
N
O
OR
Br
HH2N
N
O
OR
N
O
H
H
RO
N H
H
H
N
O
H
H
RO
N
O
OR
Br
 
 
 
 
 
 
 
 
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