Trifluoroacetic acid → (6aR,7S,9aS, 11R,12S,13aS)-5-benzyloxy-2,3,6,6a,7,8,9,9a,10,11,12,13-dodecahydro-11,12-dihydroxy-6a,7,10,10-tetramethyl-3-oxo-1H-benzo[8,8a][1]benzopyrano[2,3-e]isoindole

Participants

Reaction Steps

To a solution of Compound (48a) (30 mg, 0.051 mmol) in 2.0 ml of dry dichloromethane were added 17 μl (0.156 mmol) of anisole and 40 μl (0.51 mmol) of trifluoroacetic acid under ice-cooling, and the mixture stirred for 1 hours at room temperature. Under ice-cooling, an aqueous saturated sodium hydrogen carbonate solution was added to the reaction mixture, which was followed by extraction with ethyl acetate. The extract was washed with water and saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by a preparative thin layer chromatography (Merck, Kieselgel 60 F254, 0.5 mm; chloroform:methanol=10:1) to give 24 mg (96%) of Compound (49a).

Provenance & Evidence