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

HRID 1452821Notes

Reaction equation

S(=O)(=O)(O)O.N[C@H:7]([C:12]([OH:14])=[O:13])[CH2:8][CH:9]([CH3:11])[CH3:10].[K+].[Br-:16].N([O-])=O.[Na+]>C1(C)C=CC=CC=1.O>[Br:16][C@H:7]([CH2:8][CH:9]([CH3:11])[CH3:10])[C:12]([OH:14])=[O:13]

Participants

Conditions

Temperature: -10 °C

Procedure

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.

Workup

additionwas added for 2 hours
customwas elevated to a room temperature
customthe liquid was separated
washthe obtained organic layer was washed twice each with 30 ml of water

Sources & evidence

ORD record: ord-9af14d24b65f4d76bcb41a2f0e32c562
Source dataset: uspto-grants-2009_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07473803B2

Reaction notes

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