5-(Benzyloxy)-2-bromobenzaldehyde → 4-(Benzyloxy)-1-bromo-2-vinylbenzene

HRID 860706Notes

Reaction equation

HRID 860706 reaction equation
[CH3:1]C(C)([O-])C.[K+].[CH2:7]([O:14][C:15]1[CH:16]=[CH:17][C:18]([Br:23])=[C:19]([CH:22]=1)[CH:20]=O)[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C1OCCOCCOCCOCCOCCOC1.C1COCC1>[CH2:7]([O:14][C:15]1[CH:16]=[CH:17][C:18]([Br:23])=[C:19]([CH:20]=[CH2:1])[CH:22]=1)[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1

Participants

6

Reactant 2

HCID 108700245-(Benzyloxy)-2-bromobenzaldehydeHCID 23665647Potassium tert-butoxide

Product 1

HCID 692072164-(Benzyloxy)-1-bromo-2-vinylbenzeneYield 86.5%

Reagents, catalysts & solvents 3

HCID 2855718-Crown-6CatalystHCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 8028TetrahydrofuranSolvent

Procedure

Methyltriphenylphosphonium bromide (12.4 g, 0.0347 mol) and 18-crown-6 (90 mg, 0.41 mmol) were added to THF (100 mL). The mixture was cooled in a ice-water bath. Potassium tert-butoxide (34.7 mL of 1.0M in THF, 0.0347 mol) was added via cannula to the stirred solution. 5-(Benzyloxy)-2-bromobenzaldehyde (9.2 g, 0.0316 mol) was added in one portion which resulted in a slight exotherm. After 30 minutes the cooling bath was removed and stirring was continued at 22° C. for 5 hours. The mixture was concentrated and the residue was purified by flash column chromatography on SiO2 (75 g) with hexanes/ethyl acetate (95:5) to provide 4-(benzyloxy)-1-bromo-2-vinylbenzene as a clear oil (7.9 g, 86% yield). 1H NMR (300 MHz, CDCl3) δ 5.03 (s, 2H), 5.32 (d, J=10.98 Hz, 2H,) 5.63 (d, J=17.20 Hz, 2H), 6.74 (dd, J=8.78, 2.93 Hz, 2H), 6.98 (dd, J=17.57, 10.98 Hz, 2H), 7.13 (d, J=2.93 Hz, 2H), 7.33 (m, 6H).

Workup

  1. temperatureThe mixture was cooled in a ice-water bath
  2. customresulted in a slight exotherm
  3. customAfter 30 minutes the cooling bath was removed
  4. concentrationThe mixture was concentrated
  5. customthe residue was purified by flash column chromatography on SiO2 (75 g) with hexanes/ethyl acetate (95:5)

Sources & evidence

ORD record
ord-14b84c4dfcab448582096ef09318d304
Source dataset
uspto-grants-2006_12
Patent number
US07153848B2

Reaction notes

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