Development of Amine-Boranes And Derivatives For Reductive Amination.pdf

This dissertation focuses on the development of amine-boranes and their novel monotrifluoroacetoxy-derivatives as efficient and environmentally friendly reagents for reductive amination. Trimethyl borate, as a lewis acid, is shown to improve the chemoselectivity of amine-boranes while promoting faster imine formation. Refinement of amine-boranes via reaction with trifluoroacetic acid provides mono trifluoroacetoxyborane-amine (TFAB-amine) complexes. This new class of reagents serves as mild, chemoselective agents for the direct reductive amination of aldehydes and ketones. Among these, TFAB-NEt3 is established as superior, compared to widely-used reductive amination reagents, with improved yields even for challenging substrates. The application of the monotrifluoroacetoxy-derivatives has been extended for the synthesis of lactams from keto-acids and amino-acids via a tandem reductive amination amidation protocol.