A novel organozinc reagent 4-coumarinylzinc bromide; preparation and application in the synthesis of 4-substituted coumarin derivatives

A novel organozinc reagent, 4-coumarinylzinc bromide, was prepared by the direct oxidative addition of active zinc to 4-bromocoumarin. The resulting organozinc bromide underwent the palladium-catalyzed cross-coupling reactions with a variety of aryl halides and acid chlorides affording the corresponding coupling products in good yields under mild conditions.