Iron-Catalyzed Intermolecular Hydrothiolation of Internal Alkynes with Thiosalicylic Acids, and Sequential Intramolecular Cyclization Reaction.

We demonstrate the iron-catalyzed intermolecular coupling of internal alkynes and thiosalicylic acid derivatives. The reaction was effectively catalyzed by the Fe(acac)2/1,10-phenanthroline catalyst in toluene/HFIP (hexafluoroisopropyl alcohol) as the reaction solvent and afforded several types of 1,3-oxathiine derivatives in moderate to high yields through the intermolecular hydrothiolation and sequential intramolecular cyclization.