Three-Component C-H Bond Sulfonylation of Imidazoheterocycles by Visible-Light Organophotoredox Catalysis

The first entirely visible-light photoredox catalyzed sulfonylation of imidazoheterocycles has been developed. This transformation demonstrates an efficient C-H functionalization for the straightforward synthesis of novel C-3 sulfonylated imidazoheterocycles from various imidazopyridines and diaryliodonium salts with different electronic and steric properties and easy to handle DABCO-bis(sulfur dioxide). The reaction proceeds in moderate to good yields under mild conditions at room temperature using the inexpensive organophotocatalyst EosinY center dot Na-2 and shows a high functional group tolerance (37 examples).