Catalyst-Free Oxidative [3+2] Cycloaddition of Phenols and Styrenes in the Presence of a 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone/1,1,1,3,3,3-hexafluoropropan-2-ol System

A catalyst-free oxidative [3+2] cycloaddition of phenols and styrenes was developed with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone as the oxidant and 1,1,1,3,3,3-hexafluoropropan-2-ol as the solvent at room temperature. With this method, a broad range of dihydrobenzofurans were efficiently and quickly obtained from readily available phenols and styrenes.