Catalytically Enantioselective Synthesis of Acyclic α-Tertiary Amines through Desymmetrization of 2-Substituted 2-Nitro-1,3-diols

Highly enantioselective synthesis of acyclic alpha-tertiary amines through asymmetric desymmetrization is reported. This approach is based on chiral phosphoric acid mediated, enantioselective, oxidative desymmetrization of 2-substituted 2-nitro-1,3-diolbenzylidine acetals in the presence of DMDO as an oxidant. The method allows for the formation of a wide variety of chiral 2-nitro-1,3-diols in high enantioselectivity, which could be transformed into optically pure, unnatural alpha-alkyl series. The synthetic utility of this method has been further demonstrated by the expedient construction of the core structure of natural products manzacidins enantioselectively.