ARYL MESYLATES IN METAL-CATALYZED HOMO-COUPLING AND CROSS-COUPLING REACTIONS .4. SCOPE AND LIMITATIONS OF ARYL MESYLATES IN NICKEL-CATALYZED CROSS-COUPLING REACTIONS

This paper describes the synthetic utility of aryl mesylates derived from phenols in various transition metal-catalyzed cross-coupling reactions. The Ni(0)-catalyzed cross-couplings of aryl mesylates with organometallic carbanion synthons (organotin, -magnesium, and -zinc compounds) are described. It is demonstrated that Stille-type coupling reaction based on organotin compounds results in low yields due to the sluggish transmetalation step of the reaction cycle. Good to high yields of cross-coupled products are obtained by using more reactive organomagnesium and -zinc compounds as coupling partners. The Ni(0)-catalyzed cyanation of aryl mesylates is also described. Various aryl mesylates are converted to aryl nitriles in high yields by reaction with KCN in the presence of Ni(0) catalyst in DMF. In addition, the Ni(0)-catalyzed aromatic nucleophilic substitution reaction of aryl mesylates with the heteroatom-nucleophile, benzenethiolate anion, is also presented.