Reaction Steps
A solution of 24.3 g (84.8 mmol) of Na2CO3(H2O)10 in a mixture of 120 ml of methanol and 450 ml of water was added to a mixture of 6.30 g (33.9 mmol) of 6-bromopyridine-2-carbaldehyde, 15.6 g (33.9 mmol) of tert-butyl phenyl{[1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-naphthyl]methyl}carbamate and 1.96 g (1.70 mmol) of Pd(PPh3)4 in 600 ml of toluene by vigorous stirring at room temperature. The resulting mixture was stirred at 80° C. for 12 h. Thereafter, this mixture was cooled to room temperature, the organic layer was separated, dried over MgSO4, and then evaporated to dryness. The product was isolated by flash chromatography on silica gel 60 (40-63 um; eluent: hexanes-ethyl acetate=50:1 and then 10:1, vol.). Yield 9.50 g (64%). Anal. calc. for C28H26N2O3: C, 76.69; H, 5.98; N, 6.39. Found: C, 76.87; H, 6.12; N, 6.25. 1H NMR (CDCl3): 10.03 (s, 1H, CHO), 7.94-7.98 (m, 2H, 3,5-H in Py), 7.88 (m, 1H, 8-H in naphthyl), 7.83 (m, 1H, 4-H in Py), 7.75 (d, J=8.6 Hz, 1H, 4-H in naphthyl), 7.45 (m, 1H, 7-H in naphthyl), 7.34 (m, 1H, 6-H in naphthyl), 7.11-7.18 (m, 4H, 5-H in naphthyl and 3,4,5-H in Ph), 7.03 (d, J=8.6 Hz, 1H, 3-H in naphthyl), 6.93 (m, 2H, 2,6-H in Ph), 5.06 (d, J=15.9 Hz, 1H, CHH′N), 4.52 (d, J=15.9 Hz, 1H, CHH′N), 1.40 (s, 9H, tBu).
