Efficient and Chemoselective Reduction of Pyridines to Tetrahydropyridines and Piperidines<i>via</i>Rhodium-Catalyzed Transfer Hydrogenation
作者:Jianjun Wu、Weijun Tang、Alan Pettman、Jianliang Xiao
DOI:10.1002/adsc.201201034
日期:2013.1.14
[Cp*RhCl2]2, catalyzes efficiently the transfer hydrogenation of various quaternary pyridinium salts under mild conditions, affording not only piperidines but also 1,2,3,6‐tetrahydropyridines in a highly chemoselective fashion, depending on the substitution pattern at the pyridinium ring. The reduction is conducted in azeotropic formic acid/triethylamine (HCOOH‐Et3N) mixture at 40 °C, with catalyst loadings
在碘化物阴离子的作用下,铑络合物二聚体[Cp * RhCl 2 ] 2在温和的条件下有效催化各种季铵盐的转移氢化,不仅提供哌啶,而且还提供高度化学选择性的1,2,3,6-四氢吡啶取决于吡啶环上的取代方式。还原反应是在40°C的共沸甲酸/三乙胺(HCOOH-Et 3 N)混合物中进行的,催化剂负载量低至0.005 mol%是可行的。