19. Reactions of Aromatics: EAS and Beyond

Predict the major product from the Birch Reduction

Predict the major product from the Birch Reduction

Predict the major products of the following reactions.

(b) benzamide (PhCONH₂) + Na (liquid NH₃, CH₃CH₂OH)

Propose mechanisms for the Birch reduction of anisole. Show why the observed orientation of reduction is favored in each case.

Predict the major products of the following reactions.

(d) p-xylene + Na (liquid NH₃, CH₃CH₂OH)

(e)

A common illicit synthesis of methamphetamine involves an interesting variation of the Birch reduction. A solution of ephedrine in alcohol is added to liquid ammonia, followed by several pieces of lithium metal. The Birch reduction usually reduces the aromatic ring (Section 17-14C), but in this case it eliminates the hydroxy group of ephedrine to give methamphetamine. Propose a mechanism, similar to that for the Birch reduction, to explain this unusual course of the reaction.

Propose mechanisms for the Birch reduction of benzoic acid. Show why the observed orientation of reduction is favored in each case.

α-Tetralone undergoes Birch reduction to give an excellent yield of a single product. Predict the structure of the product, and propose a mechanism for its formation.