S-Cyanosilylenolethers: Preparation and Potential Intermediates in Synthesis

Abstract

In a previous paper we reported the direct α-phenylsulfenylation of enolates generated during different 1,4-addition reactions on α,β-unsaturated ketones¹. Since Nagata has shown that the conjugate addition of a cyano group with diethylaluminum cyanide leads to an aluminum enolate^2,3, it would be worthwile to investigate the potentiality of this reagent for simultaneous functionalisation at the α-position. Initial experiments for in situ trapping with phenylsulfenylchloride gave disappointing low yields (< 15%). However working up the initially formed aluminumenolate with trimethylchlorosilane and pyridine afforded the corresponding silylenolethers in very good yields⁴ (Table I).