Versatile β-Keto Ester and β-Keto Nitrile Synthesis through Sulfide Contraction.

Article abstract of DOI:10.1021/jo00329a017

A versatile and efficient synthesis for various β-keto esters, including those which are α substituted, is described.The α-thio iminium salt prepared from a thioamide and a primary or secondary alkylating agent is subjected to sulfur extrusion upon addition of base and a phosphine thiophile, and the result is an enamino ester which may be hydrolyzed to the desired β-keto ester.The method is also applicable to the preparation of various substituted β-keto nitriles.