Carbon tetrabromide → Methyl 4-bromo-2-(tert-butoxycarbonylamino)butanoate

HRID 910720Notes

Reaction equation

HRID 910720 reaction equation
C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[CH3:20][O:21][C:22](=[O:35])[C@H:23]([CH2:32][CH2:33]O)[NH:24][C:25]([O:27][C:28]([CH3:31])([CH3:30])[CH3:29])=[O:26].C(Br)(Br)(Br)[Br:37]>C(Cl)Cl>[CH3:20][O:21][C:22](=[O:35])[CH:23]([NH:24][C:25]([O:27][C:28]([CH3:31])([CH3:30])[CH3:29])=[O:26])[CH2:32][CH2:33][Br:37]

Participants

5

Reactant 3

HCID 11205Carbon tetrabromideHCID 11776TriphenylphosphineHCID 10561607Methyl N-(tert-butoxycarbonyl)-L-homoserinate

Product 1

HCID 6857808Methyl 4-bromo-2-(tert-butoxycarbonylamino)butanoateYield 20.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

A solution of triphenylphosphine (2.20 g, 8.39 mmol) in dry CH2Cl2 (20 mL) was added dropwise via syringe to a solution of N-Boc homoserine methyl ester 18 (8.39 mmol) and carbon tetrabromide (4.18 g, 12.60 mmol) in dry CH2Cl2 (20 mL). The resulting dark solution was stirred at room temperature for 16 h. Hexanes was added and precipitates were removed by suction filtration. The filtrate was concentrated under reduced pressure and subject to flash silica gel column chromatography using ethyl acetate/hexanes (1:10, v/v then 1:6, v/v) to give the desired product 19 as a yellow oil (501 mg, 20% overall yield from homoserine). 1H NMR (300 MHz, CDCl3) δ 1.45 (s, 9H), 2.12-2.48 (m, 2H), 3.39-3.47 (m, 2H), 3.78 (s, 3H), 4.33-4.48 (m, 1H), 5.10-5.22 (m, 1H). m/z (ESI) 296 [C10H18BrNO4+H]+.

Workup

  1. customprecipitates
  2. customwere removed by suction filtration
  3. concentrationThe filtrate was concentrated under reduced pressure

Sources & evidence

ORD record
ord-38662dda70e941f381e5b463ab401078
Source dataset
uspto-grants-2011_09
Patent number
US08022210B2

Reaction notes

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