Tetrahydrofuran → Dimethyl (3,3-dimethyl-2-oxo-4-phenylbutyl)phosphonate

To a solution of 63 g. of dimethylmethylphosphonate in 600 ml. of tetrahydrofuran under nitrogen at -75° C. is added with stirring 312 ml. of 1.6 molar n-butyllithium in hexane. The addition rate is adjusted so that the reaction temperature remains below 55° C. Ten minutes after the addition is complete, 48.2 g. of the reaction product of part B of this example and 50 ml. of tetrahydrofuran are added dropwise at such rate as to maintain the reaction temperature below -60° C. The resulting mixture is then stirred at -75° C. for 2 hr. and then ambient temperature overnight. Acetic acid (20 ml.) is thereafter added and the resulting mixture distilled under vacuum, thereby removing most of the tetrahydrofuran. The residue is then shaken with diethyl ether in methylene chloride (3:1 by volume) and a cold dilute sodium bicarbonate solution. The organic layer is then washed with brine, dried, and concentrated. The residue was crystallized from diethyl ether, yielding 54 g. of dimethyl, 3,3-dimethyl-2-oxo-4-phenylbutylphosphonate, the title compound. The melting point is 48°-50° C.

1. customremains below 55° C
2. additionTen minutes after the addition
3. temperatureto maintain the reaction temperature below -60° C
4. stirringThe resulting mixture is then stirred at -75° C. for 2 hr
5. customambient temperature overnight
6. distillationthe resulting mixture distilled under vacuum
7. customremoving most of the tetrahydrofuran
8. stirringThe residue is then shaken with diethyl ether in methylene chloride (3:1 by volume)
9. washThe organic layer is then washed with brine
10. customdried
11. concentrationconcentrated
12. customThe residue was crystallized from diethyl ether
13. customyielding 54 g

ORD record

ord-abdef6caac314ab2ae897abd9c06ca9a

Source dataset

uspto-grants-1978_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04085139