Manganese-Catalyzed Direct Transamination of Aliphatic Alcohols to Primary Amines

Aliphatic primary amines serve as essential precursors for pharmaceuticals, fine chemicals, and functional materials. However, conventional synthetic methods for these amines typically involve tedious multi-step processes with suboptimal efficiency and cost-effectiveness. Direct amination of readily available alcohols to access primary amines is highly appealing but remains challenging. Herein, we report a manganese-catalyzed transamination of alcohols using commercially available benzylamine as the amination reagent. The protocol demonstrates broad substrate compatibility and excellent selectivity toward aliphatic primary amines even at low catalyst loadings, up to 1.1×10⁶ TON could be achieved. Mechanistic studies reveal that bases play crucial roles in achieving excellent selectivity, in which tBuOK facilitates imine intermediate rearrangement and KOH acts as a nucleophile to promote imine bond cleavage, thus enabling the formation of desired primary amines instead of conventional N-alkylated secondary amines.