Tin-Catalyzed Selective Reductive Hydroamination of Alkynes for the Synthesis of Tertiary Amines

摘要

A unique preference of tin(II) for aniline activation is disclosed. In the present work tin(II) triflate-catalyzed highly selective Markovnikov reductive hydroamination of internal as well as terminal alkynes is reported. The mechanistic study revealed the involvement of two steps in one pot wherein alkyne reduces to corresponding alkene in presence of PMHS as reducing agent followed by hydroamination of alkene. A broad range of alkynes transformed into tertiary amines with good to excellent yield. This method is equally applicable in synthesis of secondary amines.