Hydroalumination-Triggered Cyclization of Silylated 1,3-Dien-5-ynes to Polysubstituted Benzenes

Regiocontrolled synthesis of polysubstituted benzenes from silylated 1,3-dien-5-ynes has been achieved by using diisobutylaluminum hydride (DIBAL-H). Hydroalumination of the alkyne moiety with DIBAL-H triggers the aromatic cyclization, which usually proceeds without rearrangement and loss of the existing substituents. The related unusual cyclizations to different types of polysubstituted benzenes are also described.