Reaction #44478

Reaction equation

O-phosphoric acid

ethyl acetate

imidazole

Tert-butyl-chloro-dimethyl-silane

Sodium borohydride

solution

1-Cycloheptyl-5-oxo-pyrrolidine-3-carboxylic acid methyl ester

→

title compound

4-(tert-Butyl-dimethyl-silanyloxymethyl)-1-cycloheptyl-pyrrolidine-2-one

Solvents

methanol

tetrahydrofuran

Conditions

Workup

1. 1
   TemperatureThe reaction was cooled to 0° C.
2. 2
   workup.STIRRINGstirred
3. 3
   FiltrationThe reaction was filtered through a pad of celite
4. 4
   Washrinsed with methanol
5. 5
   Concentrationconcentrated under vacuo
6. 6
   Washwashed with water (25 mL)
7. 7
   DryingThe organic layer was dried with MgSO4
8. 8
   Filtrationfiltered
9. 9
   Otherevaporated in vacuo
10. 10
    workup.STIRRINGstirred for three hours
11. 11
    Washwashed with water (50 mL) and brine (25 mL)
12. 12
    DryingThe organic layer was dried with MgSO4
13. 13
    Filtrationfiltered
14. 14
    Otherevaporated in vacuo
15. 15
    OtherThe crude product was purified by flash chromatography (hexanes:ethyl acetate 95:5 to 75:25)

Procedure

Sodium borohydride (0.213 g, 5.77 mmoles) was added to a solution of Example 1A (0.7 g, 2.92 mmoles) in methanol (3 mL) and tetrahydrofuran (3 mL) and stirred at 60° C. for two hours. The reaction was cooled to 0° C. and O-phosphoric acid (1.6 g, 17.4 mmoles) was added and stirred. The reaction was filtered through a pad of celite, rinsed with methanol, and concentrated under vacuo. The crude oil was taken up in ethyl acetate (25 mL) and washed with water (25 mL). The organic layer was dried with MgSO4, filtered and evaporated in vacuo. The resulting oil was taken up in N,N-dimethylformamide (4 mL) and imidazole (391 g, 5.76 mmoles) and Tert-butyl-chloro-dimethyl-silane (583 g, 3.88 mmoles) were added and stirred for three hours. The reaction was diluted with ethyl acetate (40 mL) and washed with water (50 mL) and brine (25 mL). The organic layer was dried with MgSO4 filtered and evaporated in vacuo. The crude product was purified by flash chromatography (hexanes:ethyl acetate 95:5 to 75:25) to give the title compound as a colorless oil.

Source