Selective Access to Secondary Amines by a Highly Controlled Reductive Mono-N-Alkylation of Primary Amines

A selective and direct access to secondary amines is reported by reductive mono-N-alkylation of primary amines in the presence of Ti(i-PrO)4 and NaBH4. Secondary amines are obtained exclusively from a set of carbonyl compounds and primary amines, demonstrating high chemoselectivity toward reductive mono-N-alkylation.