This work describes a base-mediated borylsilylation of benzylic ammonium salts to synthesize geminal silylboronates bearing benzylic proton under mild reaction conditions. Deaminative silylation of aryl ammonium salts was also achieved in the presence of LiOtBu. This strategy which is featured with high efficiency, mild reaction conditions, and good functional group tolerance provides efficient routes for late-stage functionalization of amines.