Iron(III) Chloride: A Versatile Catalyst for the Practical Synthesis of 3-Sulfenylindoles

The direct sulfenylation of indoles with aromatic thiols has been accomplished in the presence of 20 mol% of FeCl3 in refluxing acetonitrile to produce 3-arylthioindoles in relatively good to excellent yields and with high selectivity. This method works even with 2-unsubstituted indoles.