The Catalytic, Enantioselective F avorskii Reaction: In Situ Formation of Metal Alkynylides and Their Additions to Aldehydes

Abstract

The enantioselective addition of a metal acetylide to a carbonyl compound, known as the enantioselective Favorskii reaction, is a versatile method for the construction of enantiomerically enriched propargylic alcohols. The scope of this reaction is broad in terms of both the alkyne and the carbonyl compound employed, and under appropriate conditions, aldehydes, ketones and α‐keto esters are efficient substrates. These reactions often proceed under mild, user‐friendly conditions, and several chiral ligands have been developed that furnish products with good enantioselectivities. In this chapter, methods for accomplishing the enantioselective Favorskii reaction with various metal catalysts are discussed, as are the corresponding mechanisms. Also presented are the scope and limitations of the Favorskii reaction, and a selection of applications to the synthesis of complex molecules. A comparison of the Favorskii reaction with other methods that afford propargylic alcohol products is included.