DMSO/SOCl 2 -Enabled Synthesis of 3-Chloroindoles via Desulfonylative Chlorocyclization of N,N-Disubstituted 2-Alkynylanilines.

The application of the DMSO/SOCl 2 system enabled the intramolecular cyclization/chlorination of N,N-disubstituted 2-alkynylanilines, leading to the synthesis of a series of 3-chloroindoles with moderate to good yields. Differing from the previously reported interrupted Pummerer reaction featuring the introduction of SMe moiety, the current approach adopted an alternative pathway that realized the incorporation of chlorine atom to the indole skeleton via a desulfonylative chlorocyclization process.