反应 #1269810

反应方程式

methyl chloroformate

3-butyn-1-ol

THF

NH4Cl

Butyl lithium

→

methyl 5-(tetrahydro-2H-pyran-2-yloxy)-2-pentynoate

收率 65.0%

反应条件

后处理

1. 1
   workup.STIRRINGThe resulting mixture was stirred at about −75° C. for about 30 min
2. 2
   温度slowly warmed to about 25° C. in approximately 2 h
3. 3
   萃取The organic material was extracted with hexanes/ether, approximately 1:1
4. 4
   洗涤The combined extracts were washed with brine
5. 5
   其他dried
6. 6
   其他After removal of the solvent
7. 7
   其他on a rotary evaporator
8. 8
   其他chromatographed on silica gel with hexanes/ethyl acetate, approximately 4:1

实验过程

A solution of the THPO-ether of 3-butyn-1-ol (approximately 2.88 g, approximately 18.7 mmol) in THF (about 40 ml, dried with sodium benzophenone ketyl) was placed under N2 into a four-neck flask and cooled to about −75° C. Butyl lithium (approximately 18.7 mmol, approximately 9.4 ml of approximately 2.0 M in hexanes) was added slowly via a dropping funnel at about −75° C. The mixture was stirred at this temperature for about 30 min, and then methyl chloroformate (ClCOOMe, about 1.4 ml, about 18.7 mmol) was added. The resulting mixture was stirred at about −75° C. for about 30 min, then slowly warmed to about 25° C. in approximately 2 h and poured into a cold saturated NH4Cl solution. The organic material was extracted with hexanes/ether, approximately 1:1. The combined extracts were washed with brine and dried. After removal of the solvent on a rotary evaporator, the remainder was flash chromatographed on silica gel with hexanes/ethyl acetate, approximately 4:1, to isolate methyl 5-(tetrahydro-2H-pyran-2-yloxy)-2-pentynoate (approximately 2.5 g, approximately 65%). GC-MS (m/z, relative intensity): 211 (1, M+-1), 157 (4), 153 (3), 142 (4), 125 (18), 113 (9), 109 (11), 85 (100), 79 (41), 67 (18), 55 (16), 41 (26). 1H NMR (CDCl3): 1.50-1.64 (m, 4H), 1.72 (m, 1H), 1.83 (m, 1H), 2.66 (t, J=6.6 Hz, 2H, H-4), 3.53 (m, 1H, H-5A), 3.62 (dt, J=9.8, 7.5 Hz, 1H, H-5B), 3.77 (s, 3H, OCH3), 3.87 (m, 2H), 4.65 (br t, J=4.0 Hz, 1H, OCHO). 1H NMR data were in agreement with data obtained for this compound in CCl4 (Rama Rao et al. 1986).

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