Question

Draw mechanisms for the following reactions.

Answer 1

Given below is the detailed mechanism for the reduction of ester and ketone by LiAlH4

(a) Here ester is getting reduced to an primary alcohol. the first step is attack of hydride and loss of a OEt- group from the ester to form an aldehyde. the aldehyde is then attacked by a hydride. the intermediate is then broken down by basic aqueous solution to form the alcohol.

(b) Here a ketone is getting reduced to an secondary alcohol. The hydride attacks the carbonyl carbon to form an oxo species. Three more molecules of ketone gets attacked by the remaining hydrides on Al. Basic workup in aqueous medium yields the desired end product.

OjLi AIH2 Li AIH Eto OH OH OH OAİH, Li AI O Li OH 4