反应 #2643

反应方程式

sodium bicarbonate

tert-butyl trichloroacetimidate

boron trifluoride diethyl etherate

4-hydroxy-2-cyclopentenone

→

title compound

收率 40.0%

4-tert-butoxy-cyclopent-2-enone

收率 40.0%

溶剂

methylene chloride

反应条件

后处理

1. 1
   温度to warm to room temperature
2. 2
   workup.STIRRINGstirred for 22 hours
3. 3
   过滤filtered
4. 4
   浓缩The filtrate is concentrated under vacuum
5. 5
   其他the residue is purified by chromatography (silica gel, 39 g, 20% ethyl acetate/hexane, 600 mL)

实验过程

A solution of 4-hydroxy-2-cyclopentenone (1.15 g, 11.7 mmol) in methylene chloride is cooled to 3° C. and treated sequentially with tert-butyl trichloroacetimidate (4.2 mL, 23.7 mmol) and boron trifluoride diethyl etherate (0.15 mL). The reaction mixture is stirred at 3-10° C. for 2 hours and then allowed to warm to room temperature and stirred for 22 hours. The reaction mixture is then treated with sodium bicarbonate (250 mg) and filtered. The filtrate is concentrated under vacuum and the residue is purified by chromatography (silica gel, 39 g, 20% ethyl acetate/hexane, 600 mL) to provide the title compound (355 mg, 40%) as a yellow oil; 1H NMR (CDCl3)δ7.44 (dd, 1H, J=18 Hz), 6.2 (d, 1H, J=5.4 Hz), 4.8 (m, 1H), 2.68 (dd, 1H, J=5.8, 18 Hz), 2.25 (d, 1H, J=18 Hz), 1.27 (s, 9H); IR (neat) νmax 2976, 2936, 1721, 1368, 1352, 1188, 1103, 1161 cm-1 ; MS (CI) m/e (% relative intensity) 155 (M+H+, 22), 99 (100).

来源