Regioselective one-pot synthesis of 2,3-diaryl-2H-1-benzopyrans via Brønsted acid-catalyzed [4+2] cycloaddition of salicylaldehydes with diarylacetylenes

A regioselective one-pot synthesis of 2,3-diaryl-2H-1-benzopyrans from easily available various diarylacetylenes and salicylaldehydes via Brønsted acid-catalyzed [4+2] cycloaddition has been developed. High regioselectivity was observed in the reaction to afford 2-(electron-rich aryl)-3-(electron-poor aryl)-2H-1-benzopyrans in good yields. The present reaction provides versatile access to functionalized 2,3-diaryl-2H-1-benzopyrans, which would be useful as key intermediates for the synthesis of biologically and photochemically active molecules.