4-Bromoanisole → Tris(4-methoxyphenyl)phosphine oxide

Participants

Reaction Steps

A reaction flask under nitrogen containing magnesium turnings (223.9 g, 9.21 mol) and 1950 mL THF was charged with 1 drop of 1,2-dibromoethane and heated to reflux for 1 h. Heating was removed and p-bromoanisole (1683 g, 9.00 mol) was added dropwise at a rate to maintain reflux. After holding the reaction mixture overnight, POCl3 (460.0 g, 3.00 mol) was added slowly over 2 h at 50-79° C. and the resulting mixture was held overnight at 50° C. The product was isolated by aqueous workup to give 984.5 g of tris(4-methoxyphenyl)phosphine oxide (89.0% yield). Recrystallized analytical specimen (from ethyl acetate): mp 145.2° C. (DSC), lit. 143-144° C. (J. Org. Chem. 1960, 25, 2001).

Provenance & Evidence