Chemo- and regio-selective synthesis of hexacyclic indeno-fused coumarins via domino Diels–Alder dimerization/Baeyer–Villiger oxidation

Abstract

2-Arylindenones have been employed into two parallel chemoselective synthetic transformations. In one path, molecular oxygen was incorporated into the reaction intermediate, leading to hexacyclic benzo indeno-fused coumarins via domino head-to-head Diels–Alder dimerization/Baeyer–Villiger oxidation. On the other hand, under catalyst-free and solvent-free thermal conditions, hexacyclic indeno-fused dihydronaphthalenes were achieved through head-to-head Diels–Alder dimerization of 2/3-arylindenones. Atmospheric oxygen serves as efficient oxidant during dehydrogenative aromatization and Baeyer–Villiger rearrangement.