反应详情

温度

-100 °C

A 1.7 M solution of tert-butyl lithium (t-BuLi) in pentane (3.8 ml; 6.45 mmol) was added over ~5 minutes, to a solution of the title product of Step (B) (1 g; 3 mmol) in THF at -100° C. The temperature was kept below -84° C. during the addition. After stirring 5 minutes at -100° C., trimethylborate was added in one portion and the reaction mixture was allowed to warm to room temperature over 4 hours. At this time, 10 ml of 10% HCl was added and the mixture was extracted with methylene chloride (3×30 ml). The combined organic layers were washed with water (3×30 ml) and brine (30 ml). Drying (MgSO4), decolorizing (Darco) and concentration afforded a tan foam. Due to apparent decomposition at room temperature, the foam was stored at -80° C. overnight. The residue was then partitioned between ether (20 ml) and 0.5 N NaOH (20 ml). The purple ether layer was extracted with 10 ml of 0.5N NaOH. The combined green basic layer was washed with ether (20 ml), acidified to pH 2 with saturated KHSO4 solution to afford a purple mixture, which was extracted with methylene chloride (2×30 ml). Drying (MgSO4) and concentration afforded 623 mg (69%) of the title product of this step as a purple foam.

1. additionThe temperature was kept below -84° C. during the addition
2. temperatureto warm to room temperature over 4 hours
3. extractionthe mixture was extracted with methylene chloride (3×30 ml)
4. washThe combined organic layers were washed with water (3×30 ml) and brine (30 ml)
5. dry with materialDrying (MgSO4)
6. concentration(Darco) and concentration
7. customafforded a tan foam
8. waitDue to apparent decomposition at room temperature, the foam was stored at -80° C. overnight
9. customThe residue was then partitioned between ether (20 ml) and 0.5 N NaOH (20 ml)
10. extractionThe purple ether layer was extracted with 10 ml of 0.5N NaOH
11. washThe combined green basic layer was washed with ether (20 ml)
12. customto afford a purple mixture, which
13. extractionwas extracted with methylene chloride (2×30 ml)
14. customDrying
15. concentration(MgSO4) and concentration