Complementary Copper-Catalyzed and Electrochemical Aminosulfonylation of <i>O</i>-Homoallyl Benzimidates and <i>N</i>-Alkenyl Amidines with Sodium Sulfinates

Abstract

A complementary copper-catalyzed and electrochemical aminosulfonylation of <i>O</i>-homoallyl benzimidates and <i>N</i>-alkenyl amidines with sodium sulfinates was developed. The terminal alkene substrate produced sulfone-containing 1,3-oxazines and tetrahydropyrimidines in the presence of Cu(OAc)₂, Ag₂CO₃, and DPP, and under similar reaction conditions, sulfonylated tetrahydro-1,3-oxazepines were prepared from 1-aryl-substituted <i>O</i>-homoallyl benzimidates in moderate to good yields. For certain electron-rich 1,1-diaryl-substituted alkene substrates, the corresponding tetrahydro-1,3-oxazepines could also be obtained in similar or even higher yields via a green electrochemical technique.