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

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Reaction Steps

To a solution of dimethyl methylphosphonate (63 g.) in tetrahydrofuran (600 ml.) under nitrogen at -75°, there is added 312 ml. of 1.6 M n-butyl lithium in hexane, while maintaining the temperature below -55°. A solution of 2,2-dimethyl-3-phenylpropionyl chloride (part 2, 48.2 g.) in tetrahydrofuran is added while maintaining the temperature below -60°. The mixture is stirred at that temperature for 2 hrs. and then the temperature is allowed to rise to about 25° C. and the mixture is stirred at that temperature for 16 hrs. Acetic acid (20 ml.) is added, the mixture is concentrated, the residue is shaken with a mixture of diethyl ether-methylene chloride (3:1, v/v) and cold dilute sodium bicarbonate solution. The organic layer is separated, washed with brine, dried and concentrated. The residue is crystallized from diethylether to give the title compound, 62 g.; m.p. 48°-51°; NMR peaks at 7.2, 3.83 and 3.64, 3.28 and 2.9, 2.8 and 1.13 δ.

Provenance & Evidence