Consecutive intermolecular reductive hydroamination: cooperative transition-metal and chiral Brønsted acid catalysis

Abstract

Enantiomerically pure chiral amines are of increasing importance and commercial value in the fine chemical, pharmaceutical, and agrochemical industries. Here, we describe the straightforward synthesis of chiral amines by combining the atom-economic and environmentally friendly hydroamination of alkynes with an enantioselective hydrogenation of in situ generated imines by using inexpensive hydrogen. By following this novel approach, a wide range of terminal alkynes can be reductively hydroaminated with primary amines including alkyl-, and arylalkynes as well as aryl and heteroaryl amines. Excellent yields and selectivities up to 94 % ee and 96 % isolated yield were obtained.