反应详情

To a solution of dimethyl methylphosphonate (9.62 g, 77.0 mmol) in anhydrous THF (130 ml) was added under argon atmosphere a solution of n-butyl lithium in hexane (1.62N, 47.5 ml, 77.0 mmol) at -78° C. The reaction mixture was stirred for 30 min. and a solution of methyl 2,2-dimethyl-4-oxapentanoate (4.50 g, 30.8 mmol) in anhydrous THF (15 ml) was added at -78° C. This mixture was stirred for 30 min., allowed to warm to room temperature and stirred for 30 min. The resulting solution was neutralized with acetic acid, water (20 ml) was added, and the mixture was then concentrated. Ethyl acetate (120 ml) and water (20 ml) were added to the residue. The organic layer was separated from the aqueous layer, washed with water (50 ml), and with brine (50 ml), dried over anhydrous magnesium sulfate, and concentrated. Distillation of the residue (b.p. 104°-107° C./0.4 mmHg) gave dimethyl 3,3-dimethyl-2-oxo-5-oxahexylphosphonate (5.96 g, 25.0 mmol, 81.2%) as an oily material. The product was assigned the structure by the following data.

1. stirringThis mixture was stirred for 30 min.
2. stirringstirred for 30 min
3. additionwas added
4. concentrationthe mixture was then concentrated
5. additionEthyl acetate (120 ml) and water (20 ml) were added to the residue
6. customThe organic layer was separated from the aqueous layer
7. washwashed with water (50 ml)
8. dry with materialwith brine (50 ml), dried over anhydrous magnesium sulfate
9. concentrationconcentrated
10. distillationDistillation of the residue (b.p. 104°-107° C./0.4 mmHg)