A solution of 5.66 g (20 mmol) 1-bromo-3-iodo-benzene in 25 ml THF was stirred at −20° C. A 1.82 M solution of isopropylmagnesium chloride (12.1 ml, 22.0 mmol) in THF was added and the mixture was stirred 1 h at 0° C. The mixture was cooled to −78° C. and a solution of 5.38 g (20 mmol) 2-[(E)-tert-butoxycarbonylimino]-3,3,3-trifluoro-propionic acid ethyl ester in 50 ml of THF was added over a period of 2 h. After 20 min the mixture was quenched with 5% aqueous NH4Cl. The mixture was extracted with TBME. The organic phase was dried with Na2SO4, filtered and evaporated. Purification via chromatography on silica gel (c-hexane/0-14% EtOAc) gave the desired product as a colorless resin.
