Реакция #2200580

Уравнение реакции

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

LiAlH4

NaOH

→

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

Растворители

THF toluene

Условия реакции

Обработка

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

Методика

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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