Chlorobis((1R,2S,3R,5R)-2,6,6-trimethylbicyclo[3.1.1]heptan-3-yl)borane → (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 13 in 60 mL of THF at −23° C. was added dropwise a solution of 11.1 g (34.6 mmol) of (−)-B-chlorodiisopinocampheylborane in 30 mL of THF. After 4 h, the reaction was quenched by the dropwise addition of 5 mL of methanol and then warmed to room temperature. After pouring into 200 mL of a 2/1 mixture of ethyl acetate/saturated NH4Cl, the layers were separated, and the aqueous phase was extracted with ethyl acetate (2×100 mL). Combined organic layers were dried over MgSO4, filtered, concentrated, and the residue was chromatographed on silica gel eluting with ethyl acetate/hexanes, 3/2, to afford 4.7 g (48%) of 14 as a white solid, m.p. 101.0-102.5° C. 1H NMR δ 8.05-7.95 (m, 2 H), 7.62-7.40 (m, 3 H), 7.18 (t, J=8.0 Hz, 1 H), 7.0-6.92 (m, 1 H), 6.85 (t, J=2.1 Hz, 1 H), 6.77-6.70 (m, 1 H), 5.85 (d of d, J=6.2, 15.5 Hz, 1 H), 5.72 (d of d, J=4.5, 15.5 Hz, 1 H), 5.30 (q, J=5.8 Hz, 1 H), 5.12-5.04 (m, 1 H), 4.58-4.48 (m, 1 H), 3.92 (d of d, J=3.5, 9.3 Hz, 1 H), 3.80 (d of d, J=7.3, 9.4 Hz, 1 H), 2.9-2.2 (m, 8 H).

Provenance & Evidence