Copper(I)-Mediated and Microwave-Assisted C_aryl−O_carboxylic Coupling:  Synthesis of Benzopyranones and Isolamellarin Alkaloids

A simple and highly effective C−O_carboxylic coupling reaction catalyzed by copper(I) salts has been developed to synthesize benzopyranones. The reaction of various 2-halobiarylcarboxylic acids was examined using microwave irradiation. A new class of pyrroloisoquinoline alkaloid, isolamellarin, was synthesized based on the annulation of dihydroisoquinoline with aryl pyruvates under basic condition and Cu-mediated/MW-assisted C−O_carboxylic lactonization.