反应详情

温度

-5 °C

At -20° C., a solution of (S)-tetrahydro-1-methyl-3,3-diphenyl-1H,3H-pyrrolo(1,2-c) (1,3,2,) oxazaborole.borane complex (J. Am. Chem. Soc., 104, 5551-5553 (1987) 6.34 g, 21.8 mmol) in anhydrous THF (20 ml) was added dropwise to a solution of the ketone of Step 2 (33.1 g, 72.6 mmol) in THF (300 mL). Then, 1.0M BH3.THF (108 ml) was added slowly and the reaction mixture was slowly warmed up to -5° C. within 3-4 hours. The mixture was added to an ice cold 25% NH4OAc solution. The product was extracted into hot EtOAc, dried over Na2So4, concentrated to dryness and co-evaporated twice with toluene. It was dissolved in hot toluene and filtered through silica (~400 ml) with toluene and EtOAc:toluene 10:90 and 15:85. The product was finally recrystallized as a hydrate from toluene containing 4 mL H2O. [α ]D : +29.5° (c=1.82, CHCl3).

1. customAt -20° C.
2. extractionThe product was extracted into hot EtOAc
3. customdried over Na2So4
4. concentrationconcentrated to dryness
5. dissolutionIt was dissolved in hot toluene
6. filtrationfiltered through silica (~400 ml) with toluene and EtOAc:toluene 10:90 and 15:85
7. customThe product was finally recrystallized as a hydrate from toluene containing 4 mL H2O
8. custom+29.5° (c=1.82, CHCl3)