Tetrakis(triphenylphosphine)palladium(0) (90 mg, 0.08 mmol, 0.05 equiv) was added to a deoxygenated mixture of tert-butyl 4-iodopyridin-2-ylcarbamate (1-1, 0.500 g, 1.56 mmol, 1 equiv), 4-formylphenyl boronic acid (351 mg, 2.34 mmol, 1.50 equiv), and aqueous saturated sodium carbonate solution (2.0 M, 2.3 mL, 4.7 mmol, 3.0 equiv) in dioxane (15 mL), and the resulting mixture was heated at reflux for 18 h. The reaction mixture was cooled then concentrated. The residue was partitioned between half-saturated aqueous NaCl solution (100 mL) and EtOAc (100 mL). The organic layer was dried over sodium sulfate, and concentrated to give tert-butyl 4-(4-formylphenyl)pyridin-2-ylcarbamate (2-1) as an off-white solid. LRMS m/z (M+H) Calcd: 242.2 (minus t-Bu), 199.2 (minus Boc); found 243.0 and 199.0.
