The structural proliferation of 2,6-difluoropyridine through organometallic intermediates

Contrary to a literature claim, 2,6-difluoropyridine-3-carboxaldehyde can be readily prepared by consecutive treatment of 2,6-difluoropyridine with lithium diisopropylamide and N,N-dimethylformamide. Regioselective displacements of fluorine from the aldehyde by nucleophiles were carried out. To demonstrate the versatility of the organometallic approach, some two dozens of further 2,6-difluoropyridine derivatives were prepared applying a combination of modern organometallic methods such as site selective hydrogen/metal and halogen/metal permutations and deprotonation-triggered heavy halogen migrations. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.