New Catalysts and Methods for Highly Enantioselective Metal Carbene Reactions

Asymmetric catalysis of metal carbene transformations with unique chiral dirhodium(II) carboxamidates provides highly enantioselective, diastereoselective, and regioselective syntheses of lactones and lactams via cyclopropanation, cyclopropenation, carbon-hydrogen insertion, and ylide derived reactions of diazo acetates and diazoacetamides. Constructed from a dirhodium(II) core with bridging chiral pyrrolidone, oxazolidinone, azedinone, or imidazolidinone ligands, these catalysts are especially effective for intramolecular transformations. Reactions characteristically occur with high turnover numbers, and products are formed in high yield with enantiomeric excesses that are generally greater than 90%.