Butyltriphenylphosphonium tetraborate (BTPPTB) as a selective reducing agent for the reduction of imines, enamines and oximes and reductive alkylation of aldehydes or ketones with primary amines in methanol or under solid-phase conditions

Abstract

Butyltriphenylphosphonium tetraborate (BTPPTB) 1, generated as white solid from butyltriphenylphosphonium bromide and sodium borohydride, is found to be a selective and versatile reducing agent. The reagent in methanol or under solvent-free conditions is very useful for the reduction of imines, enamines and oximes or reductive amination of aldehydes and ketones. Under solvent-free conditions the reactions are faster and the yields of the products are higher.