반응 #79371

반응 방정식

ethyl 5-bromo-2,2-dimethylpentanoate

LiBH4

methanol

→

product

수율 101.5%

5-Bromo-2,2-dimethyl-1-pentanol

수율 101.5%

용매

methylene chloride

methylene chloride

반응 조건

후처리

1. 1
   workup.ADDITIONwas added dropwise
2. 2
   기타the temperature below 30° C
3. 3
   온도the solution was heated
4. 4
   온도under reflux for 21 h
5. 5
   온도After chilling in an ice-bath
6. 6
   기타the reaction was quenched
7. 7
   workup.ADDITIONby adding H2O dropwise (100 mL)
8. 8
   workup.ADDITION2 N HCl (125 mL) was added dropwise
9. 9
   기타The layers were separated
10. 10
    추출the aqueous layer was extracted with an additional methylene chloride (500 mL)
11. 11
    세척washed with 2 N HCl 9300 mL), then sat. NaHCO3 (300 mL)
12. 12
    건조After drying the organics over Na2SO4
13. 13
    기타the solution was evaporated

실험 절차

Under argon, a suspension of LiBH4 (14.8 g, 646 mmol) in methylene chloride (600 mL) was stirred as methanol (25.6 mL, 20.2 g, 629 mmol) was added dropwise, taking care to keep the temperature below 30° C. To this mixture, a solution of ethyl 5-bromo-2,2-dimethylpentanoate (100.0 g, 392 mmol; prepared according to Kuwahara et al. Chem. Pharm. Bull 1997, 48, 1447) in methylene chloride (200 mL) was added dropwise over 20 minutes, and the solution was heated under reflux for 21 h. After chilling in an ice-bath, the reaction was quenched by adding H2O dropwise (100 mL). After the effervescence stopped, 2 N HCl (125 mL) was added dropwise and the solution was stirred until the effervescence ceased. The procedure was repeated with another portion of 2 N HCI (125 mL). The layers were separated, and the aqueous layer was extracted with an additional methylene chloride (500 mL). The two organic portions were combined and washed with 2 N HCl 9300 mL), then sat. NaHCO3 (300 mL). After drying the organics over Na2SO4, the solution was evaporated to yield the product as a light yellow oil (77.6 g, 91% yield). 1H NMR (d6-DMSO), d (ppm): 4.42 (s, 1H); 3.45 (t, 2 H, J=6.6); 3.08 (s, 2H); 1.84-1.69 (m, 2H); 1.27 (t, 2 H, J=8.3); 0.78 (s, 6H). 13C NMR (d6-DMSO), d (ppm): 69.7, 36.9, 35.7, 34.5, 27.4, 24.0.

출처