To a stirred solution of 2-allyl-isoindole-1,3-dione (3-1) (18.9 g, 101 mmol) in degassed TBF (100 mL) at 0° C. was added dropwise a solution of 9-BBN (243 mL of 0.5M in THF, 121 mmol) and the mixture stirred for 18 hours at ambient temperature. K2CO3 (24 g, 172 mmol) and 2,5-dibromopyridine (30 g, 126 mmol) were added, followed by a premixed and aged (70° C. for 30 min) suspension of Pd(OAc)2 (2.6 g, 11.5 mmol) and DPPF (7 g, 12.6 mmol) in degassed DMF (100 mL). The resulting mixture was stirred for 18 hours at 70° C., cooled, diluted with ethyl acetate, washed with water and brine, dried over MgSO4, and concentrated. To the stirring residue dissolved in TUF (500 mL) were added water (150 mL) and NaHCO3 (33 g) and after 10 minutes, NaBO3•H2O (55 g). After vigorous stirring for 30 minutes, the mixture was diluted with ethyl acetate, washed with water and brine, dried over MgSO4, and concentrated to an oil. The residue was chromatographed on silica gel (10-20% EtOAc/hexane) to give 13 g of 3-2 as a colorless oil.
