反应详情

To a solution of the product from step 3 (9.5 g, 64.68 mol) in tetrahydrofuran (300 mL) was added sodium tert-butoxide (9.3 g, 97.02 mmol) at ice bath. Then dimethyl sulfate (13.4 g, 106 mmol) was added over 20 minutes, maintaining an internal temp below 36° C. After addition, the reaction mixture was stirred for 4 hours at room temperature. Water (200 mL) was added followed by addition of 2N HCl (100 mL). The apparent pH was below 1. After 16 hours of reaction, NaHCO3 (20 g) was added and the mixture was extracted with ethyl acetate (4×300 mL), dried over Na2SO4, filtered, and concentrated to an oil (6 g, yield: 71%).

1. temperaturemaintaining an internal temp below 36° C
2. additionAfter addition
3. additionwas added
4. extractionthe mixture was extracted with ethyl acetate (4×300 mL)
5. dry with materialdried over Na2SO4
6. filtrationfiltered