Enantioselective Cationic Polyene Cyclization vs Enantioselective Intramolecular Carbonyl−Ene Reaction

This paper describes highly efficient catalytic enantioselective cationic polyene cyclization and catalytic enantioselective intramolecular carbonyl−ene reaction in good to high yields with high enantioselectivities. The intimate relationship and mechanistic differences between the two enantioselective reactions were studied in detail. In addition, the cyclization products are versatile and useful building blocks for natural products and pharmaceuticals syntheses.