Regioselective Pd-catalyzed alkylative lactonizations of 4-hydroxy-2-alkynecarboxylates with organoboronic acids

The palladium-catalyzed addition of aryl- and alkenylboronic acids to 4-hydroxy-2-alkynecarboxylates and in situ lactonization would constitute a novel methodology for the synthesis of various butenolides with an excellent stereoselectivity and a high control of regioselectivity.