反应详情

A stirred mixture of NaBH4 (130 mg, 3.45 mmol) in H2O (3.5 mL) was added to an ice-cold solution of racemic aldehyde 12d (443 mg, 1.72 mmol) in MeOH (10 mL) that was open to the air. After addition, a gradual colour change from red to orange was observed and the reaction mixture was allowed to warm to room temperature over 20 h. The reaction mixture was poured into an ice-cooled saturated solution of aqueous NH4Cl (10 mL) and subsequently made weakly alkaline (pH 8) by addition of a saturated solution of aqueous NaHCO3. The resulting mixture was extracted with Et2O (2×20 mL). The combined organic extract was washed with H2O (1×10 mL), brine (1×10 mL), dried over Na2SO4, filtered, and all volatiles were removed in vacuo. The crude product was dissolved in Et2O and filtered through a pad of silica gel, eluting with Et2O. Evaporation of the filtrate afforded alcohol 61 (415 mg, 93%) as an orange oil: Rf=0.12 (silica, 50:50 hex/EtOAc); IR (KBr, neat) vmax 3369, 2943, 2851, 2785, 1485, 1455, 1422 cm−1; 1H NMR (300 MHz, CDCl3) δ 4.46 (AB q, 1H, J=12.3, 12.3 Hz), 4.21 (s, 5H), 4.12-3.98 (m, 1H), 3.97-3.94 (m, 1H), 3.93 (t, 1H, J=2.4 Hz), 3.48 (br s, 1H), 2.60 (s, 6H); 13C NMR (75 MHz, CDCl3) δ 112.1, 81.7, 68.7, 65.4, 62.8, 60.3, 56.2, 45.1; EIMS [m/z (%)] 259 (M+, 25), 121 (66), 86 (65), 84 (100); HRMS (EI) calcd for C13H17NO56Fe: 259.0659. Found 259.0658.

1. additionAfter addition
2. extractionThe resulting mixture was extracted with Et2O (2×20 mL)
3. extractionThe combined organic extract
4. washwas washed with H2O (1×10 mL), brine (1×10 mL)
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. customall volatiles were removed in vacuo
8. dissolutionThe crude product was dissolved in Et2O
9. filtrationfiltered through a pad of silica gel
10. washeluting with Et2O
11. customEvaporation of the filtrate