Br[C:2]1[CH:3]=[C:4]([N:8]2[C:20]3[CH:19]=[CH:18][CH:17]=[CH:16][C:15]=3[C:14]3[C:9]2=[CH:10][CH:11]=[CH:12][CH:13]=3)[CH:5]=[N:6][CH:7]=1.[Li]C(C)(C)C.C[O:27][B:28](OC)[O:29]C.Cl>C1COCC1>[CH:19]1[C:20]2[N:8]([C:4]3[CH:3]=[C:2]([B:28]([OH:29])[OH:27])[CH:7]=[N:6][CH:5]=3)[C:9]3[C:14](=[CH:13][CH:12]=[CH:11][CH:10]=3)[C:15]=2[CH:16]=[CH:17][CH:18]=1To a solution of 9-(5-bromopyridin-3-yl)-9H-carbazole (2B) (1.7 g, 5.3 mmol) in THF (20 mL) was added a solution of tert-BuLi (1.7M in hexanes, 6.8 mL, 11.6 mmol) at about −78° C. The crude mixture was then stirred at about −78° C. for about 40 min, then a freshly distilled trimethylborate (0.89 mL, 8 mmol) was added. The resulting solution was stirred at RT overnight, then a 5% HCl aqueous solution (50 mL) was added and the whole was stirred for about 20 hours. The mixture was extracted with ethyl acetate (250 mL) three times, the organic phase was collected; dried over Na2SO4, concentrated and recrystallized with hexanes/dichloromethane to give product 2C, a light yellow solid (0.9 g, 60% yield).
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