Novel α-formylation of α,α-disubstituted esters. Trimethylsilyl trifluoromethanesulphonate-catalysed reaction of ketene silyl acetals with N-t-butylformimidoyl cyanide

Abstract

General α-formylation of α,α-disubstituted methyl acetates can be achieved by the reaction of ketene silyl acetals (1) with N-t-butylformimidoyl cyanide (2) in the presence of trimethylsilyl trifluoromethanesulphonate (3) as catalyst followed by hydrolysis of the products (4) and/or (5) with copper(II) acetate or hydrogen chloride in aqueous methanol.