Organocatalytic Asymmetric Reduction of δ-Nitro Dienes: a Viable Entry to Functionalized Amines and Highly Substituted Enantioenriched Cyclopentanes

The reduction of conjugated nitroolefins is considered a powerful tool to access nitroalkanes;1 in the last few years, the organocatalytic stereoselective reduction of nitroolefins received great interest by organic chemists. In this context, the organocatalytic stereoselective reduction of ,-disubstituted nitroolefins with Hantzsch ester was firstly disclosed by List2 and further explored by other groups.3 Nevertheless, no example about the enantio-, chemo- and regioselective reduction of dienes trisubstituted at the double bond bearing the nitro group was found in the literature. Based on these considerations, a new strategy for the synthesis of -nitroalkenes from nitro dienes was disclosed, with complete chemo and regioselectivity and enantioselectivity up to 97%. The enantioenriched products were successfully elaborated and employed in the stereoselective cyclization reaction that affords an almost enantiomerically pure highly functionalised cyclopentane featuring 5 contiguous stereocenters.