Triethyl phosphite → Diethyl 2-(2-Bromoethyl)benzylphosphonate

HRID 542409Notes

Reaction equation

HRID 542409 reaction equation
[Br:1][CH2:2][CH2:3][C:4]1[CH:11]=[CH:10][CH:9]=[CH:8][C:5]=1[CH2:6]Br.[CH2:12]([O:14][P:15]([O:19]CC)[O:16][CH2:17][CH3:18])[CH3:13]>>[Br:1][CH2:2][CH2:3][C:4]1[CH:11]=[CH:10][CH:9]=[CH:8][C:5]=1[CH2:6][P:15](=[O:19])([O:16][CH2:17][CH3:18])[O:14][CH2:12][CH3:13]

Participants

3

Reactant 2

HCID 31215Triethyl phosphiteHCID 816791Alpha-bromo-2-(2-bromoethyl)toluene

Product 1

HCID 13922736Diethyl 2-(2-Bromoethyl)benzylphosphonateYield 70%

Procedure

In a round bottom flask equipped for distillation, 15.0 g (54 mmol) of 2-(2-bromoethyl)benzyl bromide and 9.0 g (54 mmol) of triethylphosphite were heated on an oil bath with stirring at 90°-100° C. When ethyl bromide ceased distilling off (1 h) the remaining volatile by-products and triethylphosphite were removed from the mixture by distillation under vacuum. The viscous oil which remained was chromatographed on a column of silica gel with hexane-ethyl acetate (1:1) as eluant. The combined fractions were concentrated under reduced pressure to yield 12.5 g (70%) of the product as a yellow oil. IR(neat): 2987, 1249, 1170, 1064, 964, 802 cm-1. 1H NMR(CDCl3) δ 1.2 (t, 6H); 3.0-4.35 (m, 10H); 7.2 (s, 4H).

Workup

  1. temperaturewere heated on an oil bath
  2. distillationWhen ethyl bromide ceased distilling off (1 h) the remaining volatile by-products and triethylphosphite
  3. customwere removed from the mixture by distillation under vacuum
  4. customThe viscous oil which remained was chromatographed on a column of silica gel with hexane-ethyl acetate (1:1) as eluant
  5. concentrationThe combined fractions were concentrated under reduced pressure

Sources & evidence

ORD record
ord-a050c56b1f934ab48e243bba72c69854
Source dataset
uspto-grants-1987_04
Patent number
US04657899

Reaction notes

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