Tetrafluoroboric acid → HCID 42639483, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 9.09 g (26.9 mmol) of the first eluting isomer diethyl (1S,2S,3R,4S)-3-(4-fluorophenyl)-4-hydroxycyclohexane-1,2-dicarboxylate (step D) and 21.5 g (53.5 mmol) of (1S)-1-[3,5-bis(trifluoromethyl)phenyl]ethyl-2,2,2-trichloroethanimidoate (step E) in 250 mL of cyclohexane/1,2-chloroethane (3/1) under nitrogen atmosphere at −5° C. was added 0.51 mL (3.58 mmol) of 54% HBF4 in ether. The reaction mixture was stirred at −5° C. to at 0° C. for 2 hr then diluted with ether. The mixture was washed with sat. aq. NaHCO3. The organic layer was dried over drying agent, filtered and the solvent evaporated under vacuum. The residue was purified by flash column chromatography on silica gel eluting with EtOAc/hexanes (1/4) to give 9.2 g of the title compound as an oil. 1H-NMR (CDCl3): δ: 7.70 (1H, s), 7.20 (2H, s), 7.00 (2H, m), 6.85 (2H, t, J=8.5 Hz), 4.43 (1 H, q, J=6.0 Hz), 4.20-4.10 (2H, m), 3.80-3.73 (2H, m), 3.36 (1H, m), 2.90-2.76 (2H, m), 2.40 (1H, m), 2.28 (1H, m), 1.63-1.55 (2H, m), 1.33 (3H, d, J=6.0 Hz), 1.25 (3H, t, J=7.2 Hz), 0.82 (3H, t, J=7.2 Hz). Unreacted starting alcohol could be recovered by flushing the column with EtOAc and reused in the above reaction.

Provenance & Evidence