91Ó°ÊÓ

Aldehyde or ketone reacts with Grignard reagent, RMgX followed by hydrolysis to form the respective alcohol depending upon the aldehyde or ketone used.

a)

Treatment of 3-methyl-2-cyclohexanone with methyl magnesium bromide followed by hydrolysis forms 1,3-dimethyl-2-cyclohexanol. This is an example of a Grignard reaction.

Formation of desired product (a)

b)

Treatment of 3-methyl-2-cyclohexanone with lithium diethyl copper forms 3-ethyl-3-methyl-2-cyclohexanone followed by hydrolysis. The given reaction is an example of a Gilman reaction. In this reaction conjugated addition occurs when organocuprate reacts with $\mathrm{Î\pm },\mathrm{β}$-unsaturated aldehyde or ketone.

Formation of the desired product (b)

c)

Treatment of 3-methyl-2-cyclohexenone with hydrogen bromide forms 3-Bromo-3-methyl-2-cyclohexanone.

Formation of desired product (c)

d)

Treatment of 3-methyl-2-cyclohexenone with ethanethiol forms 3-ethanethiol-3-methyl-2-cyclohexenone. Since conjugated addition is a more stable product because it retains the very stable carbonyl group. Therefore, weak bases form conjugated addition products.

Formation of desired product (d)