The synthesis of (±)-dihydrofomannosin acetate [5-acetoxymethyl-1-(4, 4-dimethyl-2- oxocyclopentyl)-3-oxabicyclo [4.2. 0] oct-5-en-4-one] is described. Photocycloaddition of 4- (2-acetoxy-4, 4-dimethylcyclopentyl)-2 (5H)-furanone to ethylene gave 5-(2-acetoxy-4, 4- dimethylcyclopentyl)-3-oxabicyclo [3.2. 0] heptan-2-one, which was converted into ethyl [2- acetoxymethyl-2-(2-acetoxy-4, 4-dimethylcyclopentyl) cyclobutyl] glyoxylate by the ...
