Gold(I)-Catalyzed Intermolecular Cyclopropanation of Enynes with Alkenes: Trapping of Two Different Gold Carbenes

Intermolecular cyclopropanation reactions of enynes with alkenes allows the synthesis of complex cyclic systems with gold(I) catalysts under mild conditions. Furthermore, gold carbenes are trapped intermolecularly with alkenes (see scheme; L=ligand), thereby providing experimental evidence for the involvement of two different types of metal carbenes in the skeletal rearrangement of enynes.