Toluene → (S)-tert-butyl 1-oxohexan-2-ylcarbamate

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Reaction Conditions

Reaction Steps

Under an argon gas stream, N-(tert-butoxycarbonyl)-(L)-leucine methyl ester (9.8 g, 40 mmol) as dissolved in toluene (70 ml), and cooled to -78° C. To the solution, while keeping the temperature at -60 to -70° C., was added gradually aluminum diisobutyl hydride (toluene 1.0 M solution, 52 ml). After stirring at -78° C. for 40 minutes, the cooling bath was removed, and methanol (2.1 ml) and 20% aqueous citric acid solution (30 ml) were added to the mixture, followed by extraction with ethyl acetate. The organic layer was washed with 20% aqueous citric acid solution, a saturated aqueous sodium bicarbonate solution, water and a saturated aqueous sodium chloride solution, successively. The organic layer was dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure to give (S)-2-(tert-butoxycarbonylamino)-5-methylpentanal (8.5 g).

Provenance & Evidence