合成路线1

2-Bromo-3-methylpyridine (I) is converted to the corresponding N-oxide (II) by treatment with m-chloroperbenzoic acid in CH2Cl2. Reaction of N-oxide (II) with trimethylsilyl cyanide and dimethylcarbamoyl chloride gives rise to the 2-cyanopyridine (III). Subsequent radical bromination of (III) using NBS and AIBN affords the bromomethyl pyridine (IV). Lithiation of 1-methyl-2-(triethylsilyl)imidazole (V), followed by condensation with 4-cyanobenzaldehyde (VI), provides carbinol (VII). This is then condensed with bromide (IV) in the presence of Ag2O to give ether (VIII). 5-Bromo-2,2-difluorobenzodioxole (IX) is lithiated with butyllithium in cold Et2O and subsequently treated with triisopropyl borate to afford, after aqueous work-up, the arylboronic acid (X). Finally, Mitsunobu coupling between boronic acid (X) and the bromopyridine (VIII) provides the title compound.