Synthesis of 2-Haloalkylpyridinesvia Cp*RuCl-Catalyzed Cycloaddition of 1,6-Diynes with α-Halonitriles. Unusual Halide Effect in Catalytic Cyclocotrimerization
作者:Yoshihiko Yamamoto、Keisuke Kinpara、Hisao Nishiyama、Kenji Itoh
DOI:10.1002/adsc.200505193
日期:2005.12
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
在2-5 mol%Cp * RuCl(鳕鱼)存在下,各种1,6-二炔在环境温度下与α-单卤代和α,α-二卤代腈反应,以42-93%的分离产率提供2-卤代烷基吡啶。乙腈,N,N-二甲基氨基乙腈,苯硫基乙腈和氰基乙酸甲酯作为腈底物的失败清楚地表明,α卤素取代对于在温和条件下进行本环加成反应至关重要。在一个炔烃末端上带有取代基的不对称二炔的环加成,仅得到2,3,4,6-取代的吡啶。