Gold‐Catalyzed Enantioselective Intramolecular Annulation of Ene‐Yne‐Carbonyls via Benzopyrylium‐Type Intermediates

Abstract

It has been established that a cationic gold(I)/(R)‐H8‐binap complex catalyzes the enantioselective intramolecular [4+2] annulation of benzene‐linked ene‐yne‐carbonyls via benzopyrylium‐type intermediates at room temperature to give chiral tricyclic compounds, bearing two stereogenic centers, as single diastereomers with moderate ee values. Interestingly, the reactions of sterically demanding naphthalene‐linked ene‐yne‐carbonyls with the same gold(I) catalyst gave not only [4+2] annulation products but also [3+2] annulation products as minor products with good ee values.