A series of chiral cyclometalated iridiumcomplexes have been synthesised by cyclometalating chiral 2-aryl-oxazoline and imidazoline ligands with [Cp*IrCl2]2. These iridacycles were studied for asymmetric transfer hydrogenation reactions with formic acid as the hydrogen source and were found to display various activities and enantioselectivities, with the most effective ones affording up to 63% ee
Synthesis of novel carbohydrate-based valine-derived formamide organocatalysts by CuAAC click chemistry and their application in asymmetric reduction of imines with trichlorosilane
作者:Xin Ge、Chao Qian、Xinzhi Chen
DOI:10.1016/j.tetasy.2014.10.003
日期:2014.11
organocatalysts combining carbohydrate and N-formyl-l-valine derivatives were prepared by CuII-catalyzed diazotransfer and CuI-catalyzed azide–alkyne 1,3-dipolar cycloaddition CuAACclickchemistry. It was found that the carbohydrate-based valine-derived formamide organocatalyst had high catalytic activity for the asymmetric reduction of imines with trichlorosilane. The reduction can proceed at room
Herein, we report the natural ligand quebrachitol (QCT) as a promoter for a Cu(II) catalyst, which is highly effective for N-arylation of various amines and related arylhalides. A series of diarylamine derivatives were obtained in high yields by using diethylene glycol (DEG) as both ligand and solvent. The C–N coupling reactions proceed under mild conditions and exhibit good functional group tolerance
selective N-arylation of amines or azoles with aryl halides, methyl-α-d-glucopyranoside (MG) was found to function as a green ligand of copper powder. In addition, nitrogenheterocyclic amine compounds can also undergo the N-arylation coupling with heterocyclic aryl chlorides. This process allows access to a variety of aromatic amines and aryl azoles under mild reaction conditions, has good tolerance, and
Chiral N-heterocyclic carbene-iridium complexes for asymmetric reduction of prochiral ketimines
作者:Lakshay Kathuria、Ashoka G. Samuelson
DOI:10.1016/j.poly.2020.114976
日期:2021.2
phenylglycine derived chiral NHC was shown to give the best Ir catalyst and it also gave the maximum ee compared to catalysts prepared from other NHCs in this series. The opposite enantiomer of the reduction product was always obtained while using the Ir complex bearing a valine based NHC. The yields were consistently high with a variety of imine substrates having different steric and electronic demands