Selectivity Controlled Palladium-Catalyzed Carbonylative Synthesis of Propiolates and Chromenones from Phenols and Alkynes.

An interesting selectivity-controlled palladium-catalyzed oxidative carbonylation procedure for the synthesis of propiolates and chromenones has been developed. Starting from phenols and alkynes, under slightly different conditions, various propiolates and chromenones can be isolated in moderate to good yields. Additionally, this also presents the first example of direct carbonylative annulation of nonpreactivated phenols and terminal alkynes to produce chromenones.