Reaction #1265356

Reaction equation

Phosphorus tribromide

3,5-bis(3′,5′-di-tert-butylstyryl)benzyl alcohol

Propan-2-ol

→

3,5-bis(3′,5′-di-tert-butylstyryl)benzyl bromide

Yield 85.0%

Solvents

dichloromethane

Conditions

Workup

1. 1
   Otherthe solvent was completely removed
2. 2
   OtherThe residue was purified by column chromatography over silica
3. 3
   Washeluting with dichloromethane-light petroleum (40-60) (1:9)

Procedure

Phosphorus tribromide (2.8 cm3, 30 mmol) was added to a solution of 3,5-bis(3′,5′-di-tert-butylstyryl)benzyl alcohol (1.60 g, 3.0 mmol) in dichloromethane (50 cm3) and the mixture stirred at room temperature for 3 h. Propan-2-ol (14 cm3) was added slowly and the solvent was completely removed. The residue was purified by column chromatography over silica, eluting with dichloromethane-light petroleum (40-60) (1:9), giving 3,5-bis(3′,5′-di-tert-butylstyryl)benzyl bromide (1.52 g, 85%). A sample for analysis was recrystallised from a dichloromethane-light petroleum (60-80) mixture, mp 222-223° C. (Found: C, 77.75; H. 8.72. C39H51Br requires C, 78.11; H, 8.57%); νmax(CHCl3)/cm−1 1596 s (C═C) and 964 s (C═C—H trans); λmax(CHCl3)/nm (logε) 315 (4.82); δH(400 MHz, CDCl3) 1.38 (36 H, s, t-Bu), 4.55 (2 H, s, CH2), 7.12 and 7.24 (4 H, d, J 16, 7′,8′-H), 7.39 (2 H, dd, J 1.5, 4′-H), 7.41 (4 H, d, J 1.5, 2′,6′-H), 7.47 (2 H, d, J 1, 2,6-H) and 7.63 (1 H, m, 4-H); m/z (APCI+) 521 ((M-Br)+, 100%) and 599 (M+, 40%).

Source