Gold-Catalyzed Regio- and Stereoselective Addition of Carboxylic Acids to Iodoalkynes: Access to (Z)-β-Iodoenol Esters and 1,4-Disubstituted (Z)-Enynyl Esters.

In the presence of catalytic amounts of the Au(I) cation [Au(PPh3)]+, a large variety of (Z)-β-iodoenol esters (39 examples) could be synthesized under mild reaction conditions through the regio- and stereospecific intermolecular addition of carboxylic acids to iodoalkynes. Sonogashira coupling of representative (Z)-β-iodoenol esters with terminal alkynes, alkynols, and 1,3-enynes allowed also the access to different 1,4-disubstituted (Z)-enynyl esters in excellent yields.