反应详情

To a solution of 63 g. of dimethyl methylphosphonate in 600 ml. of tetrahydrofuran under nitrogen atmosphere at -75° C. is added with stirring 312 ml. of 1.6 M n-butyllithium in hexane. The condition is regulated so as to maintain a reaction temperature below -55° C. Ten minutes after the addition, 48.2 g. of the reaction product of step B above (2,2-dimethyl-3-phenylpropionyl chloride) in 15 ml. of tetrahydrofuran is added dropswise. The dropwise addition is regulated so as to maintain a reaction temperature below -60° C. The mixture is stirred at -75° C. for 2 hr. and at ambient temperature overnight. Acetic acid (20 ml.) is added and the tetrahydrofuran is removed by distillation. The residue is shaken with diethyl ether-methylene chloride (3:1, by volume) and dilute sodium bicarbonate solution. The organic layer is washed with saturated saline and then dried and concentrated. The residue is recrystallized in diethyl ether to give 54 g. of the title compound of this preparation. Melting point 49°-51° C.

1. temperatureto maintain a reaction temperature below -55° C
2. additionTen minutes after the addition, 48.2 g
3. additionThe dropwise addition
4. temperatureto maintain a reaction temperature below -60° C
5. stirringThe mixture is stirred at -75° C. for 2 hr
6. customat ambient temperature
7. customovernight
8. customthe tetrahydrofuran is removed by distillation
9. stirringThe residue is shaken with diethyl ether-methylene chloride (3:1, by volume) and dilute sodium bicarbonate solution
10. washThe organic layer is washed with saturated saline
11. customdried
12. concentrationconcentrated
13. customThe residue is recrystallized in diethyl ether
14. customto give 54 g