10-Methylacridinium perchlorate (1) effectively promotes various reactions of ketene silyl acetals: aldol and Michael addition products are obtained with aldehydes, ketones, acetals, and α-enones. The reactions exhibit unusual dependency upon 1, namely the yields are excellent when a catalytic amount of 1 is employed whereas no desired products are accessible by the use of 1 in a stoichiometric quantity
mechanism of the Mukaiyama reaction has never been examined from the standpoint of electron transfer. We conclude here that the Lewis mediated electron transfer from hindered ketene silyl acetals to α-enones plays an essential role in connecting quaternary carbon centers. The conclusion sheds light on a novel facet of the ketene silyl acetalchemistry, and consequently relevant reactions should be reexamined