Dimethylformamide → 5-Cyano-2-(3,4-Dichlorophenoxy)-Benzaldehyde

Under N2 in a flame-dried 3-neck round bottomed flask fitted with a reflux condenser and magnetic stirrer, a mixture of 5-bromo-2-(3,4-dichlorophenoxy)-benzaldehyde (3.0 g, 8.7 mmol), zinc (II) cyanide (1.5 g, 13 mmol) and tetrakis(triphenylphosphine)palladium (0) (1.5 g, 1.3 mmol) in anhydrous DMF (145 ml) was stirred at room temperature while degassing with N2 for 5 min. After heating at approximately 80° C. for 90 min., the reaction was judged complete by thin layer chromatography (50% CH2Cl2:hexanes) and was allowed to cool to room temperature. The reaction mixture was then diluted with water and ethyl acetate (EA) and stirred another 10 min. The water layer was separated, extracted twice with EA and combined with the original EA layer, and washed with an aqueous solution of Rochelle salt (potassium sodium tartrate tetrahydrate) followed by aqueous NaCl. The organic layer was dried with Na2SO4, filtered and concentrated in vacuo to an oil. The oil was flash chromatographed on a 15×5 cm column of silica gel, eluting with CH2Cl2:hexanes (1:1) to obtain the title product as a white solid, 1.5 g (60%), m.p. 122–126° C.