l-Pipecolinic acid derived Lewis base organocatalyst for asymmetric reduction of N-aryl imines by trichlorosilane: effects of the side amide group on catalytic performances
作者:Zhouyu Wang、Chao Wang、Li Zhou、Jian Sun
DOI:10.1039/c2ob26772a
日期:——
A series of N-formamides derived from pipecolinic acid have been synthesized and tested as Lewisbase catalysts for the enantioselective reduction of N-aryl imines by trichlorosilane. Through the investigation of the structure–efficacy relationship between the side amide group and catalytic performance, several highly effective catalysts were discovered. In particular, arylamido-type catalyst 5i and
Direct Catalytic Access to N-Silylated Enamines from Enolizable Imines and Hydrosilanes by Base-Free Dehydrogenative SiN Coupling
作者:Julia Hermeke、Hendrik F. T. Klare、Martin Oestreich
DOI:10.1002/chem.201402866
日期:2014.7.21
α‐proton rather than α‐deprotonation of the enolizable imine followed by reaction with an electrophilic silicon reagent. The silicon electrophile, stabilized by a sulfur atom, is generated by cooperative activation of an SiH bond at the RuS bond of a tethered ruthenium(II) thiolate complex. After transfer of the silicon cation onto the imine nitrogen atom, the remaining ruthenium(II) hydride fulfills
The Ir-catalyzed asymmetric hydrogenation of acyclic aromatic N-aryl imines with Josiphos-type binaphane ligands has been described. Under the optimized conditions, a wide range of imines were hydrogenated to afford the corresponding chiral amines in high yields (up to 94%) and good to excellent enantioselectivities (up to >99% ee). The synthetic utility of the present protocol has been demonstrated