Seven- and eight-membered heterocyclic biaryl synthesis through a metal-free oxidative coupling reaction

A metal-free intramolecular biaryl coupling mediated by DDQ and BF3·OEt2 was developed. The reaction proceeds smoothly at room temperature to give seven- and eight-membered heterocyclic biaryl compounds in up to 95% yields. Only 1 equiv of DDQ sufficed for the reaction, obviating the use of a large excess of oxidants and undesired chlorination pathway in metal-mediated process.