反应 #2200580

反应方程式

ethyl (2S,3S)-2-methyl-3-tetrahydropyranyloxybutanoate

LiAlH4

NaOH

→

(2R,3S)-2-methyl-3-tetrahydropyranyloxybutanol

溶剂

THF toluene

反应条件

后处理

1. 1
   workup.WAITat room temperature for 30 minutes
2. 2
   workup.ADDITIONthe reaction was treated
3. 3
   workup.STIRRINGAfter having stirred for at least 30 minutes
4. 4
   过滤the mixture is filtered on Celite
5. 5
   洗涤The precipitated aluminum salts were then washed with EtOAc
6. 6
   其他The solvent was evaporated
7. 7
   其他the residual oil was purified by means of flash chromatography on a silica gel column (heptane/EtOAc=5:1

实验过程

A solution of ethyl (2S,3S)-2-methyl-3-tetrahydropyranyloxybutanoate (4) (8.18 g, 35.56 mmol) at 0° C. was added dropwise to a stirred suspension of LiAlH4 (2.70 g, 71.12 mmol) in THF/toluene (2:1) (178 ml). The reaction mixture is stirred at 0° C. for 30 minutes, and then at room temperature for 30 minutes. The reaction is neutralized by means of the “Fieser treatment”; the reaction was treated by successively adding dropwise 2.7 ml of ice-cold water, 2.7 ml of a 15% aqueous NaOH solution, and 3×2.7 ml of ice-cold water. After having stirred for at least 30 minutes, the mixture is filtered on Celite. The precipitated aluminum salts were then washed with EtOAc. The solvent was evaporated, the residual oil was purified by means of flash chromatography on a silica gel column (heptane/EtOAc=5:1 and then 2:1) in order to obtain (2R,3S)-2-methyl-3-tetrahydropyranyloxybutanol (5) in the form of a colorless oil (6.59 g, 99%): 1H NMR (250 MHz, CDCl3) δ 4.69 to 4.67 (m, 0.5H); 4.58 to 4.56 (m, 0.5H); 3.98 to 3.43 (m, 5H); 1.80 to 1.48 (m, 7H); 1.29 (d, J=6.3 Hz, 1.5H); 1.18 (d, J=6.1 Hz, 1.5H); 0.95 (d, J=7.0 Hz, 1.5H); 0.94 (d, J=7.0 Hz, 1.5H); 13C NMR (50 MHz, CDCl3) δ 99.9; 97.4; 78.4; 74.9; 65.2; 64.2; 62.7; 41.2; 40.6; 31.3; 31.0; 25.3; 25.1; 20.7; 19.8; 18.9; 17.5; 14.0; 13.0; MS (CI) m/z 189 [M+H]+. HRMS calculated for C10H21O3 (M+H), 189.14906; found, 189.14755.

来源