A 2.OM solution of 4-fluorobenzyl zinc bromide in tetrahydrofuran (95 ml, 190 mmol; Negishi, E-i. and King, A. O., J.O.C.1977,42,1821) was added dropwise over 20 minutes to a stirred solution of dimethyl 4-bromoisophthalate (20.0 g, 73.2 mmol) and tris(dibenzylideneacetone)dipalladium(O) (0.67 g,0.73 mmol) in tetrahydrofuran (270 ml) at ambient temperature under an inert atmosphere. During the addition the internal temperature rose to 40° C. The reaction mixture was stirred for 3 hours and then poured into 2M. HCl (1500 ml), cooled in an ice bath and the product extracted into ethyl acetate (3×700 ml). The extracts were washed with water (500 ml), brine (500 ml), dried, and the solvent evaporated under reduced pressure. The residue was taken up in a small quantity of dichloromethane, isohexane added, and the solid which crystallised from the solution, filtered and dried to give methyl 4-(4-fluorobenzyl)-3-methoxycarbonylbenzoate (10.5 g)
