Transition Metal Catalyzed Intramolecular Cyclizations of (Trichloromethyl)alkenes

Intramolecular Kharasch cyclizations of a variety of functionalized olefinic trichloromethyl substrates are promoted by transition-metal complexes. The regioselectivity of the cyclization is critically dependent upon the structure of the trichloromethyl compound. Thus, trichloromethyl substrate 1 afforded primarily five-membered ring exo closure product 8, as did 5a and 6, yielding mainly trichloro alcohol 12. Similarly trichloroalkene 2 gave primarily the six-membered ring exo closure product 10. Trichloromethyl ketones 7a-e, on the other hand, produced predominantly endo closure products.