[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
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) 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).
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