A Garratt–Braverman route to aryl naphthalene lignans

Abstract

A series of aryl naphthalene lignans were prepared in good yields starting from substituted bis-propargyl ethers. The method involved a base-mediated Garratt–Braverman cyclization followed by benzylic oxidation to the lactone. The chemoselectivity in the GB cyclization and the regioselectivity in the benzylic oxidation could be achieved by controlling the electronic nature of the aryl-substituents as well as by changing the substitution pattern of the two aryl rings.