Lithium tri-s-butylborohydride → (3aS,5R,7aR)-Hexahydro-2H-furo[2,3-b]pyran-5-ol

Participants

Reaction Conditions

Reaction Steps

A solution of the ketone 29 (25 mg, 0.173 mmol) dissolved in CH2Cl2 (5 mL) was cooled to −78° C. under argon. L-Selectride (1M in THF, 200 μL, 0.2 mmol) was added dropwise. The solution was stirred at this temperature for 3 h and quenched by addition of sat. aq. NH4Cl solution. The aqueous phase was extracted with EtOAc, the combined organic extract was dried (Na2SO4), filtered, and evaporated. The crude was purified by column chromatography on silica gel using hexanes/EtOAc (2:1, 1:1, then 1:2) to yield alcohol 30 as a 5:1 mixture of diastereoisomers (18 mg, cis major). The stereoisomers were separated in the subsequent synthesis of the mixed activated carbonate 31g. TLC: Rf=0.25 (hexanes/EtOAc=1:2); 1H NMR (CDCl3, 300 MHz) δ 5.08 (d, J=3.8 Hz, 0.2H), 5.05 (d, J=3.3 Hz, 1H), 4.16-4.11 (m, 1.2H), 3.95-3.84 (m, 1.6H), 3.81-3.70 (m, 2H), 3.63 (m, 1H), 3.27 (dd, J=7.9, 11.2 Hz, 0.2H), 2.35-1.70 (m, 6H).

Provenance & Evidence