Michael Addition Initiated Carbocyclization Sequences with Nitroolefins for the Stereoselective Synthesis of Functionalized Heterocyclic and Carbocyclic Systems

The synthesis of various heterocycles and carbocycles (tetrahydrofurans, pyrrolidines, cyclopentanes) has been achieved by using new and efficient ionic addition/cyclization sequences. Nitroolefins play an important role in the Michael addition induced ring‐closing reactions (MIRC) reported in the present article, with various substituted alcohols, amines, Grignard reactants, or malonate derivatives acting as the nucleophile partner. The optimized cascade reactions were high yielding in most cases and highly stereoselective, creating up to three stereogenic centers starting from achiral substrates. Complexity from simplicity: New Michael addition initiated ionic carbocyclization sequences have been developed that allow stereoselective syntheses of a variety of highly functionalized carbo‐ and heterocyclic compounds starting from simple achiral nitroolefins and a variety of nucleophiles (alcohols, amines, malonates, Grignard reagents), with the concomitant creation of three stereogenic centers (see scheme).