Rh(III)-Catalyzed Coupling of Acrylic Acids and Ynenones via Olefinic C-H Activation and Michael Addition.

Rh(III)-catalyzed coupling between acrylic acids and yndienones has been realized for the synthesis of cis-hydrobenzofuranone. The reaction proceeded in excellent regio- and stereoselectivity under mild and redox-neutral conditions via a sequence of carboxylic acid-directed olefinic C-H activation, alkyne insertion, and Michael addition. Representative products were found to exhibit cytotoxicity toward the A549 cancer cell line at micromolar levels.