A metal-free protocol for the preparation of amines using ammonia borane under mild conditions

A mild and convenient reductive amination protocol for the synthesis of structurally diverse secondary and tertiary amines as well as N-methylated products under metal-free conditions is presented. This one-pot protocol works efficiently at room temperature using ammonia borane as the reductant and is applicable to a wide range of substrates, including chiral amines and amino acid derivatives. The synthetic utility and practicability of this methodology is demonstrated by gram-scale reactions and selected synthesis of current drug molecules.