Chlorobis((1S,2R,3S,5S)-2,6,6-trimethylbicyclo(3.1.1)hept-3-yl)borane → 5-Benzoyloxy-4-[4-(3-chlorophenoxy)-3-hydroxy-1-butenyl]-hexahydro-2H-cyclopenta[b]furan-2-one

Participants

Reaction Conditions

Reaction Steps

To a solution of [3aR, 4R(1E), 5R, 6aS]-5-benzoyloxy-4-[4-(3-chlorophenoxy)-3-oxo-1-butenyl]-hexahydro-2H-cyclopenta[b]furan-2-one (1; for preparation, see published European Patent Application EP 639563 A2, which is incorporated herein by this reference) (1.02 g, 2.32 mmol) in THF (10 mL) at −23° C. (bath temperature) was added dropwise a solution of (+)-B-chlorodiisopinocampheylborane (available from Aldrich Chemical Co., Milwaukee, Wis.) (1.4 g, 4.4 mmol) in THF (10 mL). The mixture was then warmed to 0° C. (bath temperature) and was quenched after 90 min by the addition of methanol (10 mL). Saturated NH4Cl was added (35 mL), the mixture was extracted with ethyl acetate (3×40 mL), dried (MgSO4), filtered, concentrated, and chromatographed on a 30 cm tall×41 mm diameter silica gel column eluting with 1:1 ethyl acetate:hexane to afford 2 (502 mg, 49%) as well as a mixture of 2 and its epimeric alcohol (254 mg, 23%).

Provenance & Evidence