Reaction #11164

Reaction equation

2,6-dibromotoluene

NBS AIBN

bromide

triphenylphosphine

→

phosphonium

Yield 95.0%

(2,6-Dibromobenzyl)(triphenyl)phosphonium bromide

Yield 95.0%

Solvents

CH2Cl2 benzene

Conditions

Procedure

Bromination of 2,6-dibromotoluene with NBS/AIBN, followed by reaction of the crude bromide with triphenylphosphine, using the procedure described in example 102, except that the reaction time for the bromination was 3 h, gave the phosphonium salt (516) (95%) as a cream powder, mp (CH2Cl2/benzene) 241–243° C. 1H NMR (CDCl3) δ 7.78 (m, 9H), 7.64 (m, 6H), 7.40 (br d, J=7.9 Hz, 2H), 6.99 (td, J=8.0, 2.5 Hz, 1H), 5.58 (d, J=14.1 Hz, 2H). Found: C, 47.06; H, 3.37. C25H20Br3P.3/4 CH2Cl2 requires C, 47.23; H, 3.31.

Source