To 3-methyl-4-trifluoromethanesulfonyloxy-benzofuran-2-carboxylic acid ethyl ester (721 mg, 2.0 mmol, 1 eq) in 10 mL of DMF under nitrogen was added 322 mg of Zn(CN)2 (2.74 mmol, 1.37 eq), and 123 mg of Pd(PPh3)4 (0.1 mmol, 0.05 eq). The reaction mixture was heated to 85° C. The reaction was complete in 2.5 h by TLC. After work up and column chromatography eluting with 5% ethyl acetate/hexane, 4-cyano-3-methyl-benzofuran-2-carboxylic acid ethyl ester was obtained in 80% yield (367 mg). 1H NMR (400 MHz, CD3OD) δ ppm 1.6 (t, J=7.1 Hz, 3 H) 3.0 (s, 3 H) 4.6 (q, J=7.2 Hz, 2 H) 7.8 (dd, J=8.3, 7.6 Hz, 1 H) 7.9(m, 1 H) 8.1 (dd, J=8.3, 1.0 Hz, 1 H).
