Abstract: The Pd (I1)-catalyzed cyclocarbonylation of acetylenic alcohols to methylene lactones proceeds through carboalkoxypalladium intermediates, followed by intramolecular cis addition to the triple bond. Such intermediates have been independently synthesized, isolated, and found to undergo appropriate interconversions. AP~ I~/Bu~ P/CH~ CN catalyst system gives rates first order in CO pressure, with the rate-determining step evidently ...
