to afford bicyclic pyridines. Careful screening of nitrile components revealed that a C[triple chemical bond]C triple bond or heteroatom substituents, such as methoxy and methylthio groups, proved to act as the coordinating groups, whereas C==C or C==O doublebonds and amino groups failed to promote cycloaddition. This suggests that coordinating groups with multiple pi-bonds or lone pairs are essential
Scope of Ru(II)-Catalyzed Synthesis of Pyridines from Alkynes and Nitriles
作者:Jesús A. Varela、Luis Castedo、Carlos Saá
DOI:10.1021/jo035050b
日期:2003.10.1
Pyridines can be efficiently synthesized by Ru(II)-catalyzed [2 + 2 + 2] cycloaddition of 1,6-diynes to alpha,omega-dinitriles or electron-deficient nitriles or by Ru(II)-catalyzed [2 + 2 + 2] cocyclization of electron-deficient alkynes and electron-deficient nitriles. The reactions with dinitriles seem likely to proceed via ruthenacyclopentadiene intermediates and the reactions with electron-poor
Synthesis of 2-Haloalkylpyridinesvia Cp*RuCl-Catalyzed Cycloaddition of 1,6-Diynes with α-Halonitriles. Unusual Halide Effect in Catalytic Cyclocotrimerization
2–5 mol % Cp*RuCl (cod), various 1,6-diynes reacted with α-monohalo- and α,α-dihalonitriles at ambient temperature to afford 2-haloalkylpyridines in 42–93% isolated yields. The failure of acetonitrile, N,N-dimethylaminoacetonitrile, phenylthioacetonitrile, and methyl cyanoacetate as nitrile substrate clearly showed that the α halogen substitution is essential for the present cycloaddition under mild
Ruthenium-catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water
作者:Fen Xu、Chunxiang Wang、Xincheng Li、Boshun Wan
DOI:10.1002/cssc.201100744
日期:2012.5
One ring to bind them: An efficient method for synthesizing highly functionalized pyridine derivatives from diynes and nitriles is described. The reaction system involves Cp*Ru(COD)Cl/tppts‐catalyzed [2+2+2] cycloaddition in purewater. Without being accompanied by diyne dimerization or trimerization byproducts, the desired products can be obtained in moderate to high yields.