Question

Draw products formed in each of the following reaction and indicate stereochemistry.

Answer 1

(a) Acetylide ion displaces chlorine to form product A. This is a nucleophilic substitution reaction. It proceeds by $S_{n}2$ mechanism. Hence, it involves inversion of configuration.
(b) Acetylide ion displaces oxygen to form product B. In this reaction, epoxide ring opens. This is a nucleophilic substitution reaction. It proceeds by Sn1 mechanism. Hence, a racemic mixture is obtained.
(c) Acetylide ion displaces chlorine to form product C. This is a nucleophilic substitution reaction.
(d) Acetylide ion displaces oxygen to form product D. In this reaction, epoxide ring opens. This is a nucleophilic substitution reaction. It proceeds by Sn1 mechanism. Hence, a racemic mixture is obtained.