Nickel-Catalyzed Cycloaddition of Alkynes and Isocyanates
作者:Hung A. Duong、Michael J. Cross、Janis Louie
DOI:10.1021/ja046477i
日期:2004.9.1
A mild and general route for preparing 2-pyridones from isocyanates and diynes is described. Ni imidazolyidene complexes were used to mediate cyclizations between both internal and terminal diynes with aryl and alkyl isocyanates. In addition, the efficacy of this protocol allows for the preparation of a fused seven-membered pyridone and for three component cyclizations.
Ruthenium(II)-Catalyzed Cycloaddition of 1,6-Diynes with Isocyanates Leading to Bicyclic Pyridones
[GRAPHICS]A ruthenium(II) complex possessing a planar Cp* ligand, Cp*Ru(cod)Cl, effectively catalyzed the [2 + 2 + 2] cycloaddition of I,g-diynes with isocyanates to afford bicyclic pyridones in 58-87% yields.
Cp*RuCl-Catalyzed [2 + 2 + 2] Cycloadditions of α,ω-Diynes with Electron-Deficient Carbon−Heteroatom Multiple Bonds Leading to Heterocycles
In the presence of a catalytic amount of Cp*RuCl(cod), 1,6-diynes were allowed to react chemo- and regioselectively with electron-deficient nitriles and heterocumulenes at 60−90 °C to afford heterocyclic compounds. The mechanism of the ruthenium-catalyzed regioselective formations of bicyclic pyridines and pyridones were analyzed on the basis of density functional calculations. Cyclocotrimerizations
在催化量的 Cp*RuCl(cod) 存在下,1,6-二炔可以在 60-90 °C 下与缺电子腈和杂枯烯进行化学和区域选择性反应,得到杂环化合物。在密度泛函计算的基础上分析了钌催化的双环吡啶和吡啶酮区域选择性形成的机制。丙炔酸乙酯与氰基甲酸乙酯或异氰酸丙酯的环三聚反应产生四种可能的吡啶或吡啶酮区域异构体中的两种。