Synthetic Versatility of N-(Silylmethyl)imines: Water-Induced Generation of N-Protonated Azomethine Ylides of Nonstabilized Type and Fluoride-Induced Generation of 2-Azaallyl Anions

N-(Silylmethyl)imines generate N-protonated azomethine ylides of nonstabilized type when treated with water in HMPA, which undergo stereospecific and regioselective cycloadditions with electron-poor olefins affording N-unsubstituted pyrrolidines. On the other hand, fluoride-induced desilylation of the imines leads to 2-azaallyl anions which are found to be synthetic equivalents of aminomethyl anion in the Michael additions with electron-poor olefins and nucleophilic additions with carbonyl compounds.