One-Pot Synthesis of Polyfunctionalized 4H-Chromenes and Dihydrocoumarins Based on Copper(II) Bromide-Catalyzed C—C Coupling of Benzylic Alcohols with Ketene Dithioacetals.

Title reaction of benzylic alcohols (II) and (VI) with ketene dithioacetals (I) and (VIII) provides access towards 4H-chromenes (III), (IX) or dihydrocoumarins (IV), (X), resp., depending on the solvent used and on the reaction time.