Acetic Acid → Dimethyl (3,3-dimethyl-2-oxohept-5-yn-1-yl)phosphonate

Temperature

-78 °C

Under argon atmosphere, a solution of n-butyl lithium in hexane (33 ml, 0.054 mol, 1.04N) was added dropwise with stirring into a solution of dimethyl methylphosphonate (6.82 g, 0.055 mol) in anhydrous THF (100 ml) at -78° C. and the mixture was stirred for 30 min. at -78° C. To the mixture was added dropwise a solution of ethyl 2,2-dimethyl-4-hexynoate (3.7 g, 0.022 mol) in anhydrous THF (15 ml) and the mixture was stirred for 30 min. at -78° C. and then for one hour at room temperature. To the resulting mixture were added acetic acid (3.1 ml, 0.054 mol) and water (10 ml), and the mixture was then concentrated. The residue was diluted with water (20 ml) and extracted with ethyl acetate (100 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. Distillation of the residue in vacuo gave dimethyl 3,3-dimethyl-2-oxo-5-heptynylphosphonate (5.04 g, 0.020 mol, 93%, B.p.: 108°-110° C./0.15 mmHg). The product was assigned the structure by the following data.

1. stirringthe mixture was stirred for 30 min. at -78° C.
2. waitfor one hour at room temperature
3. concentrationthe mixture was then concentrated
4. additionThe residue was diluted with water (20 ml)
5. extractionextracted with ethyl acetate (100 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. distillationDistillation of the residue in vacuo

ORD record

ord-6d7f610b37d346b7b10255505a6cb169

Source dataset

uspto-grants-1988_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04775692