Syntheses of taiwaniaquinone F and taiwaniaquinol A via an unusual remote C-H functionalization.

A protecting-group-free route to (-)-taiwaniaquinone F based on a ring contraction and subsequent aromatic oxidation of a sugiol derivative is reported. In addition, the first synthesis of (+)-taiwaniaquinol A is reported via short time exposure of (-)-taiwaniaquinone F to sunlight triggering a remote C-H functionalization. The hypothesis that the biogenesis of some methylenedioxy bridged natural products could proceed via similar nonenzymatic mechanisms is presented.