反应详情

To a solution of 2.85 g (11.2 mmol) of N-t-butyl-4-n-propylbenzenesulfonamide (from Step A) in anhydrous THF (20 mL) cooled to -40° C. under N2 was added 2.5M n-butyllithium solution (11.2 mL, 2.5 equiv). The mixture was warmed to room temperature and stirred for 2 hours. To the mixture, containing the bright red dianion at 0° C., was added triisopropyl borate (3.9 mL, 1.5 equivalents). The next day, 2N HCl (3 mL) was added and the mixture was stirred for 1 hour. The solvent was removed under reduced pressure and the residue was extracted with ethyl acetate. The organic solution was washed with 2N HCl, H2O and brine. The organic phase was dried over anhydrous MgSO4 and concentrated in vacuo to afford 3.34 g (100%) of the title compound; TLC in 1:1 EtOAc-hexane (Rf =0.5). The material is used in the next step without further purification.

1. additionTo the mixture, containing the bright red dianion at 0° C.
2. stirringthe mixture was stirred for 1 hour
3. customThe solvent was removed under reduced pressure
4. extractionthe residue was extracted with ethyl acetate
5. washThe organic solution was washed with 2N HCl, H2O and brine
6. dry with materialThe organic phase was dried over anhydrous MgSO4
7. concentrationconcentrated in vacuo