Substrate dependent intramolecular palladium-catalysed cyclisation and subsequent β-H elimination or C–H activation: a general method for the synthesis of fused pyran rings

An efficient and convenient method for the synthesis of fused pyran rings via intramolecular palladium-catalysed cyclisation followed by β-H elimination or C–H activation has been developed. It is possible to utilise this method for the synthesis of benzopyran systems.