Rhodium-Catalyzed Asymmetric [2 + 2 + 2] Cyclization of 1,6-Enynes with Aliphatic and Aromatic Alkenes.

It has been established that a cationic rhodium(I)/(R)-MeO-BIPHEP complex catalyzes the asymmetric [2 + 2 + 2] cyclization of 1,6-enynes with aliphatic and aromatic alkenes to produce chiral cyclic dienes through β-hydride elimination from rhodacycle intermediates. Thus, obtained chiral cyclic dienes could be converted to chiral spirocompounds without racemization.