反应详情

The 7-methyl-3-neopentyl-2-oxo-1-oxa-3-azaspiro[4.5]decane-7-carbaldehyde intermediate product from step 1 (7.19 g, 26.9 mmol) was dissolved in THF (108 mL) and MeOH (27 mL) and treated with sodium borohydride (1.22 g, 32.3 mmol). The reaction was stirred at rt for 2 h and quenched with water (1 mL) and 1 N HCl (75 mL). The product was extracted into EtOAc (2×100 mL). The combined organics were dried over Na2SO4, filtered, and concentrated onto florisil for purification on a 120 g silica gel column (10-50% EtOAc/hexanes, 30 min gradient; 50% EtOAc/hexanes, 10 min; 50-75% EtOAc/hexanes, 10 min gradient; 85 mL/min elution; 254 nm detection) to afford the title compound (6.23 g, 75% combined yield with step 1). 1H NMR (400 MHz, CDCl3) δ 3.30-3.38 (m, 2H), 3.29 (s, 2H), 3.06 (d, J=14.05 Hz, 1H), 2.94 (d, J=14.05 Hz, 1H), 1.95-2.03 (m, 1H), 1.64-1.72 (m, 1H), 1.53-1.64 (m, 3H), 1.29-1.43 (m, 3H), 1.09 (s, 3H), 0.96 (s, 9H). MS (m/z) 270.2 (M+H+).

1. customquenched with water (1 mL) and 1 N HCl (75 mL)
2. extractionThe product was extracted into EtOAc (2×100 mL)
3. dry with materialThe combined organics were dried over Na2SO4
4. filtrationfiltered
5. concentrationconcentrated onto florisil for purification on a 120 g silica gel column (10-50% EtOAc/hexanes, 30 min gradient; 50% EtOAc/hexanes, 10 min; 50-75% EtOAc/hexanes, 10 min gradient; 85 mL/min elution; 254 nm detection)