L-Leucine, N-((1,1-dimethylethoxy)carbonyl)- → tert-butyl N-[(2S)-4-methyl-1-oxopentan-2-yl]carbamate

HRID 1588240Notes

Reaction equation

HRID 1588240 reaction equation
[C:1]([O:5][C:6]([NH:8][C@H:9]([C:14](O)=[O:15])[CH2:10][CH:11]([CH3:13])[CH3:12])=[O:7])([CH3:4])([CH3:3])[CH3:2].[H-].[Al+3].[Li+].[H-].[H-].[H-].S(=O)(=O)(O)[O-].[K+]>O>[C:1]([O:5][C:6]([NH:8][C@H:9]([CH:14]=[O:15])[CH2:10][CH:11]([CH3:12])[CH3:13])=[O:7])([CH3:3])([CH3:4])[CH3:2]

Participants

5

Reactant 3

HCID 83170L-Leucine, N-((1,1-dimethylethoxy)carbonyl)-HCID 516920Potassium bisulfateHCID 21226445Aluminium lithium hydride

Product 1

HCID 104275tert-butyl N-[(2S)-4-methyl-1-oxopentan-2-yl]carbamateYield 8.7%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A solution of N-(tert-butyloxycarbonyl)-L-leucine N,O-dimethylhydroxamide (19.80 g, 0.75 mol) in 400 mL was cooled in an ice bath under a nitrogen atmosphere while lithium aluminum hydride (3.58 g, 0.094 mole) was added as rapidly as safely possible. The resulting mixture was stirred for 30 minutes and then the reaction was stopped by addition of a solution of 25.8g of potassium bisulfate in water (400 mL). The mixture was stirred 15 minutes after addition was complete and then was filtered to give a colorless filtrate. The phases were separated. The aqueous layer was extracted with ether (2×100ml). The combined ether layer solution were washed with 1N hydrochloric acid (2×200 mL), saturated aqueous sodium bicarbonate (2×200 mL) and saturated aqueous sodium chloride (100 mL). The resulting ether solution was dried over MgSO4 and the solvent was removed under vacuum to give 13.97g of an oil. NMR indicates purity of aldehyde about 65%. This was used in subsequent reactions without purification.

Workup

  1. additionwas added as rapidly as safely possible
  2. stirringThe mixture was stirred 15 minutes
  3. additionafter addition
  4. filtrationwas filtered
  5. customto give a colorless filtrate
  6. customThe phases were separated
  7. extractionThe aqueous layer was extracted with ether (2×100ml)
  8. washThe combined ether layer solution were washed with 1N hydrochloric acid (2×200 mL), saturated aqueous sodium bicarbonate (2×200 mL) and saturated aqueous sodium chloride (100 mL)
  9. dry with materialThe resulting ether solution was dried over MgSO4
  10. customthe solvent was removed under vacuum

Sources & evidence

ORD record
ord-c9020b8e899d419497f732957027f3cc
Source dataset
uspto-grants-1993_06
Patent number
US05221665

Reaction notes

Loading…