Hexane → Dimethyl (3-methyl-2-oxooct-5-yn-1-yl)phosphonate

Temperature

-78 °C

Under argon atmosphere, to a stirred solution of dimethyl methylphosphonate (7.91 ml, 0.074 mol) in anhydrous THF (150 ml) was added dropwise a solution of n-butyl lithium in hexane (1.71N, 43 ml, 0.074 mol) and the mixture was stirred for 30 min at -78° C. A solution of ethyl 2-methyl-4-heptynoate (5.0 g, 0.03 mol) in anhydrous THF (5 ml) was dropwise added into the mixture, and the resulting mixture was stirred for 30 min. at -78° C. The resulting mixture was allowed to room temperature and 30 min. later, to the solution were then added water (10 ml) and acetic acid (45 ml) under ice-cooling, and concentrated. The residue was diluted with water (20 ml) and extracted with ethyl acetate (50 ml×2). The combined ethyl acetate layers were washed with water (20 ml) and with brine (20 ml), dried over anhydrous sodium sulfate, and concentrated. The residue was distilled to give dimethyl 3-methyl-2-oxo-5-octynylphosphonate (6.55 g, 0.027 mol, 88%, B.p.: 118°-121° C./0.35 mmHg). The product was assigned the structure by the following data.

1. stirringthe resulting mixture was stirred for 30 min. at -78° C
2. waitThe resulting mixture was allowed to room temperature and 30 min.
3. concentrationconcentrated
4. additionThe residue was diluted with water (20 ml)
5. extractionextracted with ethyl acetate (50 ml×2)
6. washThe combined ethyl acetate layers were washed with water (20 ml) and with brine (20 ml)
7. dry with materialdried over anhydrous sodium sulfate
8. concentrationconcentrated
9. distillationThe residue was distilled

ORD record

ord-4ad20b3567a9458c88f2178c850f8282

Source dataset

uspto-grants-1988_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04775692