Sulfonyl radical-enabled 6-endo-trig cyclization for regiospecific synthesis of unsymmetrical diaryl sulfones

A new sulfonyl radical-triggered 6-endo-trig cyclization of unactivated 1,5-enynes under catalytic oxidation conditions for flexible synthesis of unprecedented unsymmetrical diaryl sulfones was established. This transformation could also proceed smoothly using 2-arylalkynyl-1,1'-biphenyls, delivering new sulfonylated phenanthrenes. The synthetic utility of these transformations results in subsequent C-S and C-C bond-forming reactions to effectively build up functional sulfones with potential significance.