반응 #2200580

반응 방정식

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

LiAlH4

NaOH

→

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

용매

THF toluene

반응 조건

후처리

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
   여과the mixture is filtered on Celite
5. 5
   세척The precipitated aluminum salts were then washed with EtOAc
6. 6
   기타The solvent was evaporated
7. 7
   기타the residual oil was purified by means of flash chromatography on a silica gel column (heptane/EtOAc=5:1

실험 절차

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.

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