We report a general copper-catalyzed cross-coupling of thiols with aryl halides by using N-aryl-N'-alkyl oxalic diamide (L3) or N,N'-dialkyl oxalic diamide (L5) as the ligand. Both aryl and alkyl thiols can be coupled with unactivated aryl bromides and chlorides to give the desired products in good yields. Furthermore, this system features a broad substrate scope and good tolerance of functional groups. Importantly, the oxalic diamides are stable and can be prepared easily from commercially available and cheap starting materials.

We reportt he synthesis of thioether with high regioselectivity.T he reaction proceeds through regioselective brominationf ollowed by ac opper/oxalicd iamide-catalyzed CÀSb ond cross-coupling reaction. Functional groups, such as fluoro, chloro, trifluoromethyl, nitro, unprotecteda mine and pyridine, are tolerated by the reaction conditions. Scheme2.Scope of thiols with anisole.Scheme3.Scopeo fa reneswith thiols.Scheme4.Scopeo fp henol and aniline with thiols.Scheme5.Plausible mechanism for para-selectiveC ÀHt hioetherification.

An efficient palladium-catalyzed intramolecular decarbonylative thioetherification of 2-pyridyl thioesters to furnish 2-pyridyl aryl or alkyl thioethers is reported. Notably, PdCl 2 /PPh 3 is found to be an effective catalytic system for decarbonylative thioetherification of 2-pyridyl thioesters and is compatible under elevated temperature and strong basic conditions. This unique strategy is simple in operation and practice, uses a cheap metal-ligand catalytic system, affords the products in high yields, and has high functional group tolerance. In addition, other heterocyclic thioesters such as fur-2-yl, thiophene-2-yl, quinolin-2-yl and isoquinolin-1-yl thioesters are also consistent under the optimized reaction conditions.

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