a-氨基醇.doc

Enantioselective Synthesis of α-Substituted Ketones by Asymmetric Addition of Chiral Zinc Enamides to 1-AlkenesFull Text By Nakamura, Masaharu et al From Journal of the American Chemical Society, 125(21), 6362-6363; 2003 Preparationof(S)-2,2-dimethyl-1-(trimethylsilyloxymethyl)propylamine. A 1-L three-neck round-bottom flask was fitted with a magnetic stir bar, a reflux condenser and an additional funnel. The flask was charged with sodium borohydride (8.63 g, 228 mmol) and THF (275 mL). To a resulting suspension, (L)-tert-leucine (12.46 g, 95 mmol) was added in one portion. A solution of iodine (24.13 g, 95 mmol) in THF (75 mL) was added dropwise through the additional funnel over 30 min at 0 °C. After evolution of hydrogen gas ceased, the reaction mixture was heated to reflux for 1 day and then cooled to 0 °C. Methanol was added cautiously until the mixture become clear, then the solvent was removed with rotary evaporator to obtain a white paste, which was then dissolved to 20% aqueous KOH (200 mL). The solution was stirred for 4 h and extracted with methylene chloride (100 mL, five times). The organic extracts were dried over sodium sulfate and concentrated in vacuo to obtain a white solid (S-tert-leucinol, 100%). Enantioselective Synthesis of the C8-C20 Segment of Curvicollide CFull Text By Koerner, Marleen and Hiersemann, Martin From Organic Letters, 9(24), 4979-4982; 2007 Amino Alcohol S15: To an ice-cooled solution of (S)-t-leucine (65.6 g, 500 mmol, 1.0 eq) and sodium borohydride (45.4 g, 1200 mmol, 2.4 eq) in THF (500 mL, 1 mL/mmol) was slowly added a solution of iodine (126.9 g, 500 mmol, 1.0 eq) in THF (250 mL, 0.5 mL/mmol) over a period of 1.5 h (vigorous H2 formation!). The reaction mixture was warmed to room temperature and stirred for 30 min. The reaction mixture was subsequently refluxed for 19 h, cooled to 0 °C and then carefully treated with MeOH (150 mL, 0.3 mL/mmol). The solvents were removed under reduced pressure and the crude product was dis