反应详情

To a solution of 54 (68 mg, 0.610 mmol) and tert-butyl carbazate (81 mg, 0.613 mmol) in MeOH (5 mL) was added ground molecular sieves (115 mg, 3 Å). The mixture was stirred for 3 h after which it was filtered through celite and evaporated. The residue was dissolved in dry THF (3 mL) and AcOH (3 mL). NaBH3CN (95 mg, 1.51 mmol) was added and the solution was stirred over night. The reaction mixture was diluted with saturated NaHCO3 solution (6 mL) and EtOAc (6 mL). The organic phase was washed with brine, saturated NaHCO3, brine, dried over MgSO4 and evaporated. The cyanoborane adduct was hydrolyzed by treatment with MeOH (3 mL) and 2 M NaOH (1.9 mL). The mixture was stirred for 2 h and the MeOH was evaporated. H2O (5 mL) and DCM (5 mL) were added and the water phase was extracted three times with DCM. The combined organic phases were dried and evaporated. Purification by flash column chromatography (toluene/ethyl acetate 9:1 with 1% triethylamine and toluene/ethyl acetate 6:1 with 1% triethylamine) provided the title compound (85 mg, 61%) as an oil.

1. filtrationwas filtered through celite
2. customevaporated
3. dissolutionThe residue was dissolved in dry THF (3 mL)
4. stirringthe solution was stirred over night
5. washThe organic phase was washed with brine, saturated NaHCO3, brine
6. dry with materialdried over MgSO4
7. customevaporated
8. stirringThe mixture was stirred for 2 h
9. customthe MeOH was evaporated
10. additionH2O (5 mL) and DCM (5 mL) were added
11. extractionthe water phase was extracted three times with DCM
12. customThe combined organic phases were dried
13. customevaporated
14. customPurification by flash column chromatography (toluene/ethyl acetate 9:1 with 1% triethylamine and toluene/ethyl acetate 6:1 with 1% triethylamine)