Regioselective cycloadditions of N-protonated azomethine ylides and 2-azaallyl anions generated from N-(silylmethyl) thioimidates, synthetic equivalents of …
A water-induced-desilylation method and a direct-desilylation method have been applied to N-(silylmethyl) thioimidates to lead to the generation of N-protonated azomethine ylides and 2-azaallyl anions, respectively. These reactive intermediates are captured as cycloadducts to electron-deficient olefins, aldehydes, and ketones. The reactions with unsymmetrically substituted olefins are highly regioselective but with reverse selectivity. Regioisomeric 1- ...