Catalytic and selective synthesis of lactones and bis-lactones by palladium acetate/1,4-bis(diphenylphosphino)butane system under syngas conditions

The combination of palladium acetate and 1,4-bis(diphenylphosphino)butane (dppb) proved once again to form an effective catalytic system for the selective cyclocarbonylation of 2-allyl phenols and other bis-2-allyl phenol systems such as steroids and other important compounds. The reactions afforded new important five-, six- and seven-membered ring lactones and bis-lactones. The seven-membered ring lactones were predominant in most reactions.