Qing Li, Ying Tian, Ya-Nan Jia, Dazhi Sun, Shuang-Feng Yin, Rui Feng, Li-Jun Wu
An efficient Pd-catalyzed cyclization/sulfonylation reaction of N -allylbromoacetamides with Na 2 S 2 O 4 and allyl esters via “SO 2 ” insertion has been developed, enabling the first synthesis of 2-pyrrolidinone-functionalized allylic sulfones.
An efficient Pd-catalyzed cyclization/sulfonylation reaction of N -allylbromoacetamides with Na 2 S 2 O 4 and allyl esters via “SO 2 ” insertion has been developed, enabling the first synthesis of 2-pyrrolidinone-functionalized allylic sulfones. In this protocol, inexpensive and readily available Na 2 S 2 O 4 functions dually as a sulfur dioxide source and a single-electron donor, thereby sustaining the catalytic cycle. The reaction exhibits a broad substrate scope and excellent tolerance to diverse functional groups, affording a wide range of allylic sulfones with exclusive ( E ) selectivity. Mechanistic studies suggest a reaction pathway involving intramolecular radical cyclization, the insertion of “SO 2,” and subsequent allylic substitution of a π-allyl-Pd(II) intermediate in a single reaction.