To a dioxane solution (5 mL) of 240 mg (0.857 mmol) of 3-chloro-5-(3-chloro-5-hydroxyphenoxy)benzonitrile (B-4) was added 363 mg (1.12 mmol) of cesium carbonate. This was stirred for 30 minutes at 25° C. and then 217 mg (1.12 mmol) of t-butyl bromoacetate (5-1) was added and the reaction was stirred until the LC/MS analysis indicated that the reaction was complete. The solids were then removed by filtration and the filtrate was concentrated and purified on a CombiFlash silica column eluted with an ethyl acetate:hexanes gradient to recover desired product 5-2 as an oil. Rf=0.9 (EtOAc:hexanes 1:4). MS: M+1=395. 1H NMR(CDCl3): 1.49 (s, 9H), 4.49 (s, 2H), 6.48 (t, 1H), 6.66 (t, 1H), 6.74 (t, 1H), 7.14 (m, 1H), 7.21 (m, 1H), 7.38 (m, 1H).
