Copper-catalyzed C2-selective alkynylation of chromones via 1,4-conjugate addition

Abstract

Copper-catalyzed selective alkynylation with N-propargyl carboxamides as nucleophiles has been successfully developed for the synthesis of C2-functionalized chromanones. Under optimized reaction conditions, 21 examples were obtained in one-pot procedure through 1,4-conjugate addition. This protocol features readily available feedstocks, easy operations and moderate to good yields, which provides viable access to pharmacologically active C2-functionalized chromanones.