Copper-Catalyzed 1,4-Trifluoromethylthio-Arylsulfonylation of 1,3-Enynes via the Insertion of Sulfur Dioxide

A copper-catalyzed trifluoromethylthio-arylsulfonylationbetween1,3-enynes, AgSCF3, aryldiazonium tetrafluoroborates, andSO(2) (from SOgen) is presented, which could introduce sulfone,SCF3, and allene moieties into one molecule simultaneously.This strategy features mild reaction conditions, good substrate compatibility,and excellent regioselectivity. The products obtained have the potentialfor further conversion into other valuable compounds. Initial investigationsinto the reaction mechanism suggest that it may proceed via a radicalpathway. Notably, SOgen was proven as a uniquely effective SO2 surrogate in this transformation.