2,4-Dinitrobenzoate → (3aS,4S,7aR)-Octahydrobenzofuran-4-ol

Participants

Reaction Steps

Racemic alcohol 12 (70 mg, 0.5 mmol) was dissolved in THF (5 mL), vinyl acetate (120 μL, 1.25 mmol) was added. Amano lipase PS-30 (30 mg) was added and the resulting suspension was stirred at 15-17° C. After 48 h, 30 mg additional enzyme was added and the mixture was left for additional 48 h until which ca. 54% conv. was reached (NMR and GC). The resulting suspension was diluted with Et2O and filtered on celite, the filter cake rinsed with Et2O. After evaporation of the remaining solvent, the residue was purified by column chromatography using hexanes/EtOAc (5:1, 3:1 then 2:1) as the eluent to yield acetyl furanol 13 (38 mg, 41%) and the desired enantioenriched (−)-hexahydrobenzofuranol (−)-12 (24 mg, 35%). The enantiomeric excess of the 2,4-dinitrobenzoate derivative of (−)-12 was determined to be 98.8% ee by chiral HPLC, Column ChiralPak IA, hexane/isopropanol (90/10 to 50/50, 40 min), 1 mL/min, 35° C., λ=254 nm, Rt Major=16.54 min, Rt minor=37.1 min.

Provenance & Evidence