Jiao's group has recently reported chlorination of (hetero)arenes with
N-chlorosuccinimide (NCS) and a catalytic amount of
DMSO. The reaction is applied to a wide variety of (hetero)arenes such as indoles, pyridines, and thiophenes with high yields and high regioselectivity. Furthermore, the chlorination proceeds in drugs such as naproxen and diclofenac, natural products like papaverine hydrochloride and podophyllotoxin, and side chains of tyrosine residues in peptides. The chlorination can be carried out under neutral and mild condition, so it is expected to be applied to the drug discovery and development in late-stage synthesis. Furthermore, ease of handle and milder condition can be regarded as advantages compared with copper-mediated chlorinations with C-H activation.
2,3)