Abstract
Anemonin (1) was synthesized by photochemical dimerization of protoanemonin (2). Thus, a methanol solution of (2) was irradiated at -50°C under a 250 W high pressure mercury lamp to obtain a crystalline dimer (1), mp 153°C, and polymers.Catalytic hydrogenation of (1) yielded tetrahydroanemonin, which, with subsequent oxidation with potassium permanganate, gave dilevulinic acid, mp 158°C. Tetrahydroanemonin was reduced with lithium aluminium hydride to obtain a tetraol derivative (8), which showed no signal in its n.m.r. spectrum less than 4τ and was not oxidized with lead tetraacetate. The configuration of (1) has thus been established to be (9).
