Coupling of thiols and aromatic halides promoted by diboron derived super electron donors

We have proven that pyridine-boryl complexes can be used as superelectron donors to promote the coupling of thiols and aromatic halides through a S RN 1 mechanism. The reaction is efficient for a broad substrate scope, tolerating heterocycles including pyridines, enolizable or reducible functional groups. The method has been applied to intermediates in drug synthesis as well as interesting functionalized polythioethers through a controlled and consecutive intramolecular electron transfer process. Diboron-based super electron donors (SEDs) efficiently catalyze the coupling between thiols and aryl halides through a S RN 1 mechanism. Remarkably, under the optimized conditions, the competitive borylation reaction of the aryl halides is suppressed.