Sulfuric Acid → (2R)-2-bromo-4-methylpentanoic acid

Participants

Reaction Conditions

Reaction Steps

Concentrated sulfuric acid (16.16 g, 0.16 mol) was slowly added to 110 g of water and, successively, L-leucin (8.68 g, 0.066 mol) and KBr (39.4 g, 0.33 mol) were added successively. The slurry was cooled to −10° C. and sodium nitrite dissolved in 12.9 g of water (7.0 g, 0.10 mol) was added for 2 hours. After stirring at −10° C. over one night, 50 ml of toluene was added, temperature was elevated to a room temperature and the liquid was separated. The aqueous layer was discarded and the obtained organic layer was washed twice each with 30 ml of water to obtain a toluene solution of (R)-2-bromo-4-methyl valeric acid. When the optical purity of (R)-2-bromo-4-methyl valeric acid was evaluated by HPLC, it was 92.0% ee.

Provenance & Evidence