The dihydrobenzofuran scaffolds demonstrate a wide range of biological activities. Several transition metals have been employed as catalysts for the efficacious synthesis of these structurally important frameworks.
As a carbene precursor, diazo compounds incorporate in Rh-catalyzed synthesis of heterocycles, carbocycles and functionalized compounds. The reaction involves C–H activation, carbene insertion and an annulation/functionalization sequence.
Metal-free C–H insertion via flow photolysis of aryldiazoacetates 3–5 with increased reaction efficiency in the presence of 4,4′-dimethoxybenzophenone.
Remote C(sp3)–H bond functionalization reactions are environmentally benign methods for not only acyclic molecules but also cyclic molecules, 2,3-disubstituted dihydrobenzofurans.
This review mainly focus on the assembly of chiral benzoheterocycles, such as dihydrobenzofurans, chromans, indolines, tetrahydroquinolines, etc., via Earth-abundant metal-catalyzed (Cu, Fe, Ni, and Ti) asymmetric synthesis in the last few decades.