Nickel-Catalyzed Cross-Electrophile Coupling of Triazine Esters with Aryl Bromides

Cross-electrophile coupling of triazine esters with aryl bromides could be facilely accomplished by employing nickel as catalyst, magnesium as metal mediator, and lithium chloride as additive. The reactions proceeded efficiently in THF at room temperature through C-O bond activation to afford an array of structurally different diaryl ketones in moderate to good yields with wide functional group tolerance. Control experiments showed that nickel, magnesium, lithium chloride, and THF are all indispensable for the good performance of the coupling reaction. Preliminary mechanistic exploration indicated that in situ formed arylmagnesium reagent by the insertion of magnesium into aryl bromide might serve as the key intermediate of the cross-coupling. The method which avoids the utilization of moisture-labile and relatively difficult-to-obtain organometallics is step-economical, cost-efficient, and operationally simple, potentially serving as an attractive alternative to documented methods. An efficient nickel-catalyzed cross-electrophile coupling of triazine esters with aryl bromides in the presence of magnesium powder and lithium chloride in THF is reported. The cross-coupling reactions proceeded smoothly at room temperature to afford a variety of structurally diverse diaryl ketones in moderate to good yields with wide functional group tolerance.image