反应详情

温度

-10 °C

To a solution of the alcohol of Step 4 (28.2 g, 0.20 mol) and Et3N (82 mL, 0.59 mol) in CH2Cl2 (1 L) cooled to -40° C. was added methanesulfonyl chloride (43.5 mL, 0.3 mol). The reaction mixture was warmed to -10° C. for 20 min and then an aqueous solution of NaHC03 was added. The product was extracted with CH2Cl2, washed with brine and dried over Na2SO4. A portion of this mesylate (0.053 mol) was then dissolved in DMF (180 mL) and cooled to 0° C. Freshly prepared cesium thiol acetate (J. Org. Chem., 51, 3664, (1986)) (22 g, 0.11 mol) was added and the mixture was stirred overnight at r.t. The reaction mixture was poured into an aqueous solution of NaHCO3 and extracted with Et2O. The organic phases were washed with brine and dried over Na2SO4. The residual oil was then purified by flash chromatography with 10:1 hexane:EtOAc to yield 7.5 g, 70%, of the title compound. 1H NMR (CDCl3) δ0.60 (4H, m), 2.30 (2H, s), 2.35 (3H, s), 3.03 (2H, s), 3.70 (3H, s).

1. additionan aqueous solution of NaHC03 was added
2. extractionThe product was extracted with CH2Cl2
3. washwashed with brine
4. dry with materialdried over Na2SO4
5. temperaturecooled to 0° C
6. extractionextracted with Et2O
7. washThe organic phases were washed with brine
8. dry with materialdried over Na2SO4
9. customThe residual oil was then purified by flash chromatography with 10:1 hexane
10. customEtOAc to yield 7.5 g, 70%