Synthetic preparation of N-alkyl and N-aryl arenesulfinamides using an arenesulfinic acid-CDI driven approach

A new synthetic methodology has been developed for the synthesis of N-alkyl and N-aryl arenesulfinamides. The methodology involved reacting arenesulfinic acids (R = -Me, -H, -Cl) with 1,1'-carbonyldiimidazole (CDI) to form the reactive intermediate, an arenesulfinylimidazole. This intermediate was then reacted with both primary and secondary amines to yield the corresponding N-alkyl sulfinamides in yields up to 90%. While the overall yields ranged from 52% to 90%, the level of diastereoselection with racemic or enantiomerically enriched amines only reached a level of 54:46 favoring the major diastereomer as determined by analysis of the 500 MHz H-1 NMR spectra. A series of aniline derivatives were also investigated as coupling partners and were found to form the N-aryl arenesulfinamide in good yield.