Gold(I)-Catalyzed Inter- and Intramolecular Additions of Carbonyl Compounds to Allenenes

The gold(I)-catalyzed intramolecular reaction of allenes with oxoalkenes leads to bicyclo[6.3.0]undecane ring systems, although in the case of terminally disubstituted allenes, seven-membered rings are formed. The related intermolecular addition of aldehydes to allenenes also gives seven-membered rings.