title: Lithiation of 2-chloro- and 2-methoxypyridine with lithium dialkylamides: initial ortho-direction or subsequent lithium ortho-stabilization?
abstract: The lithiation pathway of 2-chloro and 2-methoxypyridine with LDA and LTMP has been investigated using deuterated probes. The availability of both H-6 and H-3 protons on the pyridine nucleus was found to be critical to ensure complete C-3 lithiation. We thus concluded that the C-3 lithiation was not a straightforward process. A mechanism involving precomplexation of lithium dialkylamides near the H-6 proton and formation of a 3,6-dilithio pyridine intermediate is proposed.
authors.affiliation: Synthèse Organique et Réactivité, UMR CNRS-UHP 7565, Faculté des Sciences, Université Henri Poincaré-NancyI, BP 239, 54506, Vandoeuvre-Lès-Nancy, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Gros
authors.forename: Sabine
authors.initials: S
authors.lastname: Choppin
authors.forename: Yves
authors.initials: Y
authors.lastname: Fort