反应详情

To 10% Pd/C (220 mg) under nitrogen was added a soln of tert-butyl 4-(4-(benzyloxy)-phenyl)-5-fluoro-5,6-dihydropyridine-1(2H)-carboxylate (1.35 g, 3.5 mmol) in ethyl acetate (20 mL). The mixture was stirred at rt under a hydrogen atmosphere at balloon pressure for 45 min. The Pd/C was removed by filtration, and the filtrate was concentrated. The residue was purified via silica gel chromatography (40 g of silica gel) eluting with a gradient of 0-100% ethyl acetate in hexanes to give the product cis-tert-butyl 4-(4-(benzyloxy)phenyl)-3-fluoropiperidine-1-carboxylate (1.05 g, 2.7 mmol, 77% yield). LC/MS (Conditions CZ-1) (M−t-butyl, AcCN+H)+=371.25. RT=1.504 min; 1H NMR (500 MHz, chloroform-d) δ 7.45 (d, J=7.6 Hz, 2H), 7.40 (t, J=7.5 Hz, 2H), 7.34 (t, J=7.0 Hz, 1H), 7.22 (d, J=8.4 Hz, 2H), 6.96 (ddd, J=8.9, 2.7, 2.0 Hz, 2H), 5.07 (s, 2H), 4.79-4.60 (m, 1H), 4.55-4.23 (m, 2H), 3.08-2.81 (m, 2H), 2.75 (ddd, J=36.0, 13.4, 3.1 Hz, 1H), 2.21 (qd, J=12.9, 4.3 Hz, 1H), 1.69 (d, J=11.7 Hz, 1H), 1.59 (s, 3H), 1.51 (s, 9H). The structure of this compound was verified by single-crystal X-ray analysis.

1. customThe Pd/C was removed by filtration
2. concentrationthe filtrate was concentrated
3. customThe residue was purified via silica gel chromatography (40 g of silica gel)
4. washeluting with a gradient of 0-100% ethyl acetate in hexanes