Imine compounds azomethine ylide generation

As mentioned above, the quaternarization method using N-silylmethyl-imines [Eq. (2)] offers an even more general and convenient method of azomethine ylide generation than the original N-silylmethylation method shown by Eq. (1). Another advantage is the ready availability of N-silylmethylimines, which are conveniently prepared by the condensation of carbonyl compounds with silylmethylamine or with silylmethyl azide in the presence of triphenylphosphine (84JOC2688). 

Nitrile oxides are often generated by the dehydration of nitro compounds by reagents such as phenyl isocyanate. Azomethine ylides can be generated by the pyrolysis of aziridines or by the prototopic isomerization of imines upon heating. 

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