Synthesis of 1H-pyrano[4,3-b]benzofuran-1-one derivatives via photochemical cyclization of substituted 4H-furo[3,2-c]pyran-4-ones

A novel approach for synthesis of fused 1H-pyrano[4,3-b]benzofuran-1-ones was developed based on the photochemical reaction of 2,3-disubstitued 4H-furo[3,2-c]pyran-4-ones. The studied process includes the photocyclization of the hexatriene system and subsequent aromatization of benzene ring via elimination of water molecule. The structure of one of the 1H-pyrano[4,3-b]benzofuran-1-one derivatives was determined by X-ray diffraction. (C) 2020 Elsevier Ltd. All rights reserved.