反应详情

温度

-100 °C

To a stirred solution of anhydrous tetrahydrofuran (100 cm3) cooled to −100° C. in an ethyl ether/liquid nitrogen bath under an atmosphere of dry nitrogen was added a 2M solution of lithium diisopropylamide (6.30 cm3, 12.7 mmol) in tetrahydrofuran followed by dropwise addition at −100° C. of a solution of (3,4-dichloro-phenoxy)-acetic acid allyl ester (3.00 g, 11.5 mmol) in anhydrous tetrahydrofuran (15 cm3) over 5 minutes. The solution was stirred at −100° C. for 1 hour and the supernatant (3.30 cm3, 11.8 mmol) of a centrifuged 1:1 mixture of chlortrimethylsilane and triethylamine was added dropwise over 5 minutes at −100° C. The solution was stirred an additional 1 hour at −100° C. and allowed to warm to ambient temperature. To the solution was added 1 N sodium hydroxide (250 cm3) and the mixture stirred 10 minutes at ambient temperature. The aqueous layer was separated, extracted with ethyl ether (2×50 cm3) and acidified with 1 N HCl to pH 1.0. The acidified aqueous was extracted with ethyl ether (3×50 cm3), the combined ethyl ether extracts washed with brine (50 cm3), dried over magnesium sulfate, vacuum filtered and the filtrate volatile fractions removed in vacuo to afford a 4:1 mixture of the title compound and (3,4-dichloro-phenoxy)-acetic acid as a pale yellow solid (1.12 g, 37.3%) with negative ESI (M−H)−260.1.

1. additionwas added dropwise over 5 minutes at −100° C
2. stirringThe solution was stirred an additional 1 hour at −100° C.
3. temperatureto warm to ambient temperature
4. stirringthe mixture stirred 10 minutes at ambient temperature
5. customThe aqueous layer was separated
6. extractionextracted with ethyl ether (2×50 cm3)
7. extractionThe acidified aqueous was extracted with ethyl ether (3×50 cm3)
8. washthe combined ethyl ether extracts washed with brine (50 cm3)
9. dry with materialdried over magnesium sulfate, vacuum
10. filtrationfiltered
11. customthe filtrate volatile fractions removed in vacuo
12. customto afford