Реакция #50176

Уравнение реакции

Tetrahydro-2-(2-propynyloxy)-2H-pyran

tetrahydro-4H-pyran-4-one

ethyl magnesium bromide

→

4-hydroxy-4-[3-(tetrahydropyran-2-yloxy)prop-1-ynyl]tetrahydropyran

Выход 88.3%

Растворители

THF

Условия реакции

Обработка

1. 1
   ДругоеThe reaction was quenched by addition of crushed ice and saturated aqueous NH4Cl
2. 2
   ЭкстракцияThe resulting two-layered mixture was extracted with ether (3×150 mL)
3. 3
   СушкаThe combined organic layers were dried over MgSO4
4. 4
   Фильтрацияfiltered
5. 5
   Концентрированиеconcentrated in vacuo
6. 6
   ДругоеPurification by chromatography on silica gel (200 g, 20% ethyl acetate: hexanes)

Методика

Tetrahydro-2-(2-propynyloxy)-2H-pyran (21 g, 150 mmol) was converted to the corresponding magnesium anion by deprotonation with ethyl magnesium bromide (75 mL of a 2M solution, 150 mmol) according to the method described in Org. Synth., 60: 81, 7 (1981). The resulting anion was cooled to -20° C. and tetrahydro-4H-pyran-4-one (14.8 g, 148 mmol) in dry THF (30 mL) was added dropwise and the resulting solution stirred for three hours. The reaction was quenched by addition of crushed ice and saturated aqueous NH4Cl. The resulting two-layered mixture was extracted with ether (3×150 mL). The combined organic layers were dried over MgSO4, filtered, and concentrated in vacuo. Purification by chromatography on silica gel (200 g, 20% ethyl acetate: hexanes) provided 4-hydroxy-4-[3-(tetrahydropyran-2-yloxy)prop-1-ynyl]tetrahydropyran(31.4 g, 88%).

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