Organic redox cascade cyclization of 2-alkynylquinones by ascorbic acid in combination with a copper catalyst and its application to formal synthesis of liphagal†
Abstract
A stoichiometric amount of ascorbic acid in combination with CuCl2ยท2H2O catalyst was found to promote the organic redox cascade transformation of alkynylquinones, successfully furnishing hydroxybenzofuran derivatives. By applying the present organic redox-driven copper-catalyzed cyclization protocol, a formal synthetic route to liphagal has been developed.