Palladium-catalyzed carbonylative lactonization of propargyl alcohols with organic dichalcogenides and carbon monoxide

The reaction of propargylic alcohols with diaryl disulfides and carbon monoxide in the presence of tetrakis(triphenylphosphine)palladium results into a novel thiolative lactonization to produce beta-(arylthio)-alpha,beta-unsaturated lactones in moderate to good yields. Similar conditions can be used with homopropargylic alcohols, providing the corresponding delta-lactones with a beta-arylthio group. The reaction employing diaryl diselenides instead of diaryl disulfides also leads to a similar one-pot thiolation/lactonization sequence to produce the corresponding beta-selenobutenolides.