(3aR,4R,5R,6aS)-4-((E)-4-(3-Chlorophenoxy)-3-oxobut-1-en-1-yl)-2-oxohexahydro-2H-cyclopenta[b]furan-5-yl benzoate → (3aR,4R,5R,6aS)-5-(Benzoyloxy)-4-[(E)-(3R)-4-(3-chlorophenoxy)-3-hydroxy-1-butenyl]-hexahydro-2H-cyclopenta[b]furan-2-one

Participants

Reaction Steps

To a solution of 9.70 g (22.0 mmol) of enone 26 in 60 mL of THF at -23° C. was added dropwise a solution of 11.1 g (34.6 mmol) of (-)-DIPCl in 30 mL of THF. After 4h, the reaction was quenched at -23° C. by the dropwise addition of 5 mL of methanol, and was warmed to room temperature. The mixture was then poured into 200 mL of a 2:1 mixture of ethyl acetate: saturated NH4Cl, the layers were separated, and the aqueous phase was extracted with 2 X 100 mL portions of ethyl acetate. The combined organic layers were dried over MgSO4, concentrated, and the residue was flash chromatographed on a 33 cm tall×76 mm diameter silica gel column eluting with 3:2 v/v ethyl acetate:hexanes to afford 4.7 g (48%) of 27 as a white solid, m.p. 101.0°-102.5° C. 1H NMR δ 8.05-7.95 (m, 2H), 7.62-7.40 (m, 3H), 7.18 (t, J=8.0 Hz, 1H), 7.0-6.92 (m, 1H), 6.85 (t, J=2.1 Hz, 1H), 6.77-6.70 (m, 1H, 5.85 (d of d, J=6.2, 15.5 Hz, 1H), 5.72 (d of d, J=4.5, 15.5 Hz, 1H), 5.30 (q, J=5.8 Hz, 1H), 5.12-5.04 (m, 1H), 4.58-4.48 (m, 1H), 3.92 (d of d, J=3.5, 9.3 Hz, 1H), 3.80 (d of d, J=7.3, 9.4 Hz, 1H), 2.9-2.2 (m, 8H).

Provenance & Evidence