Rhodium-catalyzed arylative cyclization for the enantioselective synthesis of (trifluoromethyl)cyclobutanols.

A rhodium-catalyzed cyclization of 1-(trifluoromethyl)-4-alkyn-1-ones with arylboronic acids is described to yield a novel class of small rings: (trifluoromethyl)cyclobutanols bearing an exocyclic double bond. The use of a rhodium/chiral diene complex allowed the reaction to proceed under mild conditions, often with high enantioselectivity. An X-ray crystal structure was obtained confirming the formation of the four-membered ring products.