[2,3] Sigmatropic Rearrangement of Allylic <i>S</i>-Acylsulfonium Ylide Intermediates Generated from Rhodium-Catalyzed Addition of Diazo Compounds

Allyl thioesters, thiocarbonates, thiocarbamates, and thiocyanates are shown to undergo rhodium-catalyzed addition of carbene groups, generated from diazo compounds, to afford <i>S</i>-acyl sulfonium ylides that undergo [2,3] sigmatropic rearrangement. Competing side reactions such as cyclopropanation and [1,2] acyl shifts are not observed. The reaction works with a variety of sulfur functional groups, including thioesters, thiocarbonates, thiocarbamates, and thiocyanates, affording densely functionalized products. The reaction works well with trimethylsilyldiazomethane (TMSD) and α-aryl diazoesters.