A rhodium-catalyzed chelation-assisted C−H activation of α,β-unsaturated ketoximes and the reaction with alkynes to afford highly substituted pyridine derivatives is described. ... Treatment of α,β-unsaturated ketoxime 1a having methyl substituents at α- and β-carbons with diphenylacetylene 2a in the presence of 3 mol % of RhCl(PPh 3 ) 3 in toluene at 130 °C for 3 h gave a highly substituted pyridine derivative 3a in 92% isolated yield (Table 1, entry 1). To the best of our ...
