Abstract A convergent synthesis of heteroarotinoids 4, 5a, and 5b, bearing chromene rings in association with pyridyl or ethynylpyridyl moieties, from 6-bromo-2-pyridylzinc chloride (11) is described. This new functional heteroarylzinc reagent, readily accessible from 2, 6- dibromopyridine, may undergo a selective palladium-catalyzed carbon− carbon bond- forming reaction to yield the corresponding 6-substituted-2-bromopyridines 13. Further ...
