Benzene, 4-bromo-1-ethenyl-2-methyl- synthesis

Yield:943741-00-2 76%

Reaction Conditions:

with potassium fluoride;tetrabutyl-ammonium chloride;tris-(dibenzylideneacetone)dipalladium⁽⁰⁾ in toluene at 170; for 0.5 h;Molecular sieve;

Steps:

30A

3OA: 4-bromo-2-methyH-vinylbenzene; [00347] KF (870 mg, 15 mmol), K-Bu₄NCl (2.77 g, 10 mmol), Pd(dba)₂ (145 mg, 0.25 mmol), molecular sieves (4 Ang, 200 mg, activated balls), 5-bromo-2-iodo- 1-methylbenzene (1.49 g, 5 mmol), trimethyl(vinyl)silane (2.7 mL, 20 mmol), and toluene (10 mL) were added to a pressure vessel and sparged with Ar. The vial was sealed and microwaved at 170⁰C for 30 min. The mixture was cooled to ambient temperature, diluted with hexanes, filtered and concentrated. The crude oil was purified by flash chromatography (100% hexanes) to yield 3OA (750 mg, 76%) as a clear oil. ¹H NMR (400 MHz, CDCl₃) δ ppm 2.31 (s, 3 H) 5.31 (dd, /=10.99, 1.10Hz, 1 H) 5.62 (dd, J=17.59, 1.10 Hz, 1 H) 6.84 (dd, J=17.04, 10.99 Hz, 1 H) 7.26 - 7.35 (m, 3 H).

References:

WO2007/76431,2007,A1 Location in patent:Page/Page column 145