Diastereoselective bicyclization of enynols via gold catalysis

A Au(I)-catalyzed protocol for the cycloisomerizations of enynols into 4.3.0 (hetero)bicycles with complete regio- and diastereoselection is herein described. The sequential bicyclization exploits substrates with a styryl arm, disclosing in turn a reactive pathway that is complementary to the literature reports. The use of a gold(I)–phosphite catalyst allowed for the synthesis of functionalized polycycles under mild conditions, with good yields and low catalyst loadings (1 mol%).