Metal- and base-free syntheses of aryl/alkylthioindoles by the iodine-induced reductive coupling of aryl/alkyl sulfonyl chlorides with indoles

An Iodine-catalysed process for an efficient and scalable sulfenylation protocol for indoles employing aryl-/alkyl sulfonyl chlorides has been developed. A series of sterically and electronically divergent aryl-/alkyl sulfonyl chlorides participated in the sulfenylation of C(sp 2 )-H bonds, resulting in a high to excellent yield of indole 3-sulfenylether molecules. It is noteworthy that indole-3-thiomethyl ether is efficiently generated with methanesulfonyl chloride as an electrophile, indicating the potential of this methodology. Iodine-induced reductive coupling of aryl/alkyl sulfonyl chlorides with indoles leading to various substituted aryl/alkylthioindoles has been accomplished.