Hexane → Dimethyl (2-cyclopentyl-2-oxoethyl)phosphonate

Temperature

0 °C

To a stirred solution of dimethyl methylphosphonate (11.55 g, 0.093 mol) in 150 ml of anhydrous THF at -78° C. was added dropwise a solution of n-butyl lithium in hexane (1.67N, 56.1 ml, 0.094 mol) under argon atmosphere, and the mixture was stirred for 30 minutes. To this reaction mixture was added a solution of methyl cyclopentanecarboxylate (5.0 g, 0.039 mol) in 10 ml of anhydrous THF. After being stirred for 30 minutes, the reaction mixture was allowed to warm to 0° C. and stirred for 1 hour. The reaction mixture was diluted with 5.4 ml of acetic acid and 10 ml of water, and concentrated. 30 ml of water was added to the residue. The mixture was extracted with ethyl acetate (100 ml×2). The combined organic layers were washed with water (20 ml) and brine (20 ml), dried over anhydrous sodium sulfate, and concentrated. The residue was distilled under reduced pressure to give a colorless transparent oil of dimethyl 2-cyclopentyl-2-oxo-ethylphosphonate (7.65 g, 0.035 mol, yield 89.1%, b.p. 106°-108° C./0.2 mmHg), which was assigned the structure by the following data:

1. stirringAfter being stirred for 30 minutes
2. stirringstirred for 1 hour
3. concentrationconcentrated
4. addition30 ml of water was added to the residue
5. extractionThe mixture was extracted with ethyl acetate (100 ml×2)
6. washThe combined organic layers were washed with water (20 ml) and brine (20 ml)
7. dry with materialdried over anhydrous sodium sulfate
8. concentrationconcentrated
9. distillationThe residue was distilled under reduced pressure

ORD record

ord-ee8cccc0c36d4a34b03c4501cbe03200

Source dataset

uspto-grants-1988_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04775692