Ammonium Chloride → 4-Bromo-1-isopropoxy-2-vinylbenzene

Temperature

0 °C

To a suspension of methyltriphenylphosphonium bromide (41.1 g, 115 mmol) in anhydrous THF (1.2 L) was added n-butyllithium (123 mmol, 2.5 M in hexanes) at −70° C. The mixture was stirred for a further 10 min, and then allowed to warm up to 0° C. and stirred at this temperature for 10 min. The reaction mixture is then cooled again at −50° C., and 5-bromo-2-isopropoxybenzaldehyde (20.0 g, 82.2 mmol) in solution in anhydrous THF (5 mL) was added. The mixture was stirred for 10 min, and then allowed to warm up to room temperature. An ammonium chloride solution was added and the reaction mixture was diluted with a mixture methyl t-butylether/hexane, filtered through celite, and then dried over magnesium sulfate. The solvent was removed in vacuo to afford compound AY (18.9 g) as a pale yellow oil in 95% yield. 1H NMR (CDCl3, 400 MHz): δ (ppm) 1.34 (d, J=6.0 Hz, 6H), 4.50 (sept., J=6.0 Hz, 1H), 5.27 (dd, J=11.0 and 1.1 Hz, 1H), 5.71 (dd, J=17.9 and 1.2 Hz, 1H), 6.75 (d, J=8.7 Hz, 1H), 6.97 (dd, J=17.7 and 11.2 Hz, 1H), 7.28 (dd, J=8.7 and 2.5 Hz, 1H), 7.57 (d, J=2.5 Hz, 1H).

1. stirringstirred at this temperature for 10 min
2. temperatureThe reaction mixture is then cooled again at −50° C.
3. stirringThe mixture was stirred for 10 min
4. temperatureto warm up to room temperature
5. filtrationfiltered through celite
6. dry with materialdried over magnesium sulfate
7. customThe solvent was removed in vacuo
8. customto afford compound AY (18.9 g) as a pale yellow oil in 95% yield

ORD record

ord-b50acbbcaeab4948b9e9aac40ad50f79

Source dataset

uspto-grants-2012_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08309737B2