H31O6: [M + H]+ 403.2115; found 403.2118. Synthesis of (3S,3aR,3a1R
H31O6: + 403.2115; located 403.2118. Synthesis of (3S,3aR,3a1R,6aR,7S,7aS,11aR,11bS)-7-hydroxy-5,five,eight,8-tetramethyl-15methylene-3,3a,7,7a,eight,11b-hexahydro-1H-6a,11a-(epoxymethano)-3,3a1ethanophenanthrodioxine-9,14(2H)-dione (19) To a solution of 18 (10 mg, 0.025 mmol) in dichloromethane (two mL) was added PDC (11.2 mg, 0.03 mmol) at…