A Simple Enantioselective Route to Functionalized Indolizidines: Synthesis of (+)‐Ipalbidine and (+)‐Antofine

Abstract

Abstract An efficient route to functionalized indolizidines from an enantiomerically enriched γ‐nitro ketone is described. The nitro ketone is obtained by an organocatalytic, enantioselective ketone‐nitro alkene Michael addition. Oxidative ring expansion of the nitro ketone and subsequent methanolysis provides a 8‐nitro‐4‐oxooctanoate. This is stereoselectively transformed to the key, functionalized indolizidine intermediate which is readily converted to (+)‐ipalbidine and (+)‐antofine.