3,4-Bis(2-methylbutyloxy)benzeneboronic acid synthesis

Yield:501434-69-1 98%

Reaction Conditions:

Stage #1: 3,4-bis(2-methylbutyloxy)benzeneboronic acid;2-bromo-4,4'-di-tert-butylbiphenylwith potassium carbonate in water;toluene; for 1 h;
Stage #2: tetrakis(triphenylphosphine) palladium⁽⁰⁾ in water;toluene; for 8 h;Heating / reflux;Suzuki Coupling;
Stage #3: with sodium cyanide in water;toluene; for 2 h;

Steps:

A1.2

Preparation of 5'-t-butyl-2'-(4"-t-butylphenyl)-2,3-bis(2-methylbutyloxy)biphenyl 205.5 g (0.595 mol) of 2-bromo-4,4'-di-t-butylbiphenyl, 188.7 g (0.641 mol) of 3,4-bis(2-methylbutyloxy)benzeneboronic acid and 177.2 g (1.282 mol) of K₂CO₃ were suspended in 840 ml of toluene and 840 ml of H₂O and the mixture was saturated with N₂ for 1 hour. 1.48 g (1.28 mmol) of Pd(PPh₃)₄ were subsequently added under protective gas and the mixture was stirred vigorously under reflux for about 8 hours under a blanket of protective gas. 630 ml of 1% strength NaCN solution were added and the mixture was stirred for 2 hours. The organic phase washed three times with water, dried over Na₂SO₄, filtered and subsequently evaporated completely on a rotary evaporator. This gave 300.2 g (98%) of a light-brown oil which, according to ¹H NMR, had a purity of 97% and was used directly in the subsequent reaction. ¹H NMR (CDCl₃, 500 MHz): [ppm]=7.5-7.3 (m, 3H); 7.23 (m, 2H); 7.08 (m, 2H); 6.81-6.87 (m, 2H); 6.51 (d, 1H); 3.87-3.7 (m, 2H, OCH₂); 3.44-3.30 (m, 2H, OCH₂); 1.88 (m, 1H, H-C); 1.71 (m, 1H, H-C); 1.62-1.42 (m) 2H, CH₂); 1.39 (s, 9H, C(CH₃)₃); 1.29 (s, 9H, C(CH₃)₃); 1.10-1.33 (m, 4H, CH₂); 1.07-0.83 (m, 12H, 4*CH₃).

References:

US2007/265473,2007,A1 Location in patent:Page/Page column 12