[C:1]1([C@H:7]([NH2:9])[CH3:8])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.C[Al](C)C.[F:14][C:15]1([F:22])[CH2:21][CH2:20][CH2:19][CH:18]2[CH:16]1[O:17]2.[F-].[Na+]>ClCCl>[F:14][C:15]1([F:22])[CH2:21][CH2:20][CH2:19][C@@H:18]([NH:9][C@@H:7]([C:1]2[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=2)[CH3:8])[C@@H:16]1[OH:17]
A solution of (1R)-1-phenylethanamine (30, 72 mL, 0.57 mol) in dichloromethane (200 mL) was cooled to 0° C. and treated with trimethylaluminum (260 mL, 0.52 mol) and the resulting solution was stirred for 1 hour at 0° C. To this solution was added a solution of 2,2-difluoro-7-oxabicyclo[4.1.0]heptane (66 g, 0.49 mol) in dichloromethane (200 mL) and the resulting mixture stirred at 0° C. for 3 hours. The reaction was then warmed to ambient temperature for 16 hours. The reaction was cooled to 0° C., treated with 103 g of sodium fluoride and then quenched with water (90 mL, slow addition). The reaction was warmed to ambient temperature, the solids filtered and the solution evaporated in vacuo. Purification by flash chromatography (50-100% ethyl acetate in hexanes) gave 36.3 g (29%) of (1S,6R)-2,2-difluoro-6-{[(1R)-1-phenylethyl]amino}cyclohexanol 31 (plus 32 g of 1R,6S diastereomer) as a white solid: 1H NMR (500 MHz, CDCl3) δ 7.32 (5H, s), 3.90 (1H, q, J=6.6 Hz,), 3.39 (1H, ddd, J=19.8, 9.8, 4.2 Hz), 2.70 (1H, m), 2.11 (1H, m), 1.80 (1H, m), 1.62 (2H, m), 1.43 (1H, m), 1.36 (3H, d, J=6.6 Hz), 0.96 (1H, m).
Loading…
