O-Silylation and Attempted O-Alkylation of Lithium Ester Enolates. The Synthesis of O-Silyl Ketene Acetals

Abstract

The reaction of ketone enolates with alkylating or silylating reagents can be used to prepare O-alkyl or O-silyl vinyl ethers^1. An analogous reaction of ester enolates would produce O-alkyl (I) or O-silyl (II) ketene acetals^2. Such a simple route to ketene acetal structures would appear to

be of major synthetic value^3. Consequently, we have studied the reaction of lithium ester enolates, obtained from the corresponding esters and lithium N-isopropylcyclohexylamide (LiICA)⁴ as shown in eq. 1, with a

variety of alkylating and silylating reagents.