反应详情

温度

0 °C

1.3 equivalents of n-butyllithium are added to a suspension of 122 mg (0.35 mmol) of chloromethyltriphenylphosphonium chloride in tetrahydrofuran cooled to 0° C. After stirring for one hour, the ylide is added at 0° C., via a hollow tube, to 55 mg (0.25 mmol) of methyl 3-oxo-2,3-dihydro-1-benzoxepin-7-carboxylate, prepared according to example 31. Immediately afterwards, water, 1N hydrochloric acid and dichloromethane are added. The phases are separated and then the aqueous phase is extracted three times with dichloromethane. The combined organic phases are washed with brine, are then dried and are finally concentrated under vacuum. The crude reaction product is then purified by chromatography on silica gel (ethyl acetate/heptane 5/95) to provide 61 mg (96%) of methyl 3-(chloromethylene)-2,3-dihydro-1-benzoxepin-7-carboxylate in the form of a yellow-white solid comprising two Z/E isomers as a mixture in an 85/15 ratio; M.p.=72–77° C.

1. customprepared
2. customThe phases are separated
3. extractionthe aqueous phase is extracted three times with dichloromethane
4. washThe combined organic phases are washed with brine
5. customare then dried
6. concentrationare finally concentrated under vacuum
7. customThe crude reaction product
8. customis then purified by chromatography on silica gel (ethyl acetate/heptane 5/95)