Complementary C-H Functionalization Mode of Benzoylacetonitriles: Computer-Augmented Study of a Regio- and Stereoselective Synthesis of Functionalized Benzofulvenes

A highly regio- and stereoselective synthesis of functionalized benzofulvenes via Rh(III)-catalyzed cascade reactions of benzoyl acetonitrile/methylsulfone/acetate with propargyl alcohols is presented herein. Mechanistic modeling performed with density functional theory (DFT) calculations suggested that the hydroxyl group and CsOAc played important roles in mediating the 5-membered ring cyclization by forming a very thermodynamically stable Rh(III) intermediate. Another remarkable feature of this transformation is its excellent stereoselectivity in that only E-isomers are obtained.