We present herein an unprecedented diastereoconvergent synthesis of vicinal diamines from diols through an economical, redox-neutral process. Under cooperative ruthenium and Lewis acid catalysis, readily available anilines and 1,2-diols (as a mixture of diastereomers) couple to forge two C−N bonds in an efficient and diastereoselective fashion. By identifying an effective chiral iridium/phosphoric
Highly Enantioselective Imino Pinacol Coupling Leading to the Synthesis of 1,2-Diphenylethylenediamine Derivatives
作者:Makoto Shimizu、Toyoshi Iida、Tamotsu Fujisawa
DOI:10.1246/cl.1995.609
日期:1995.7
Enantioselective imino pinacol coupling of p-anisylbenzalimine was promoted by the use of Zn-Cu couple in the presence of (+)-camphorsulfonic acid to give (R,R)-1,2-diphenylethylenediamine derivative in high enantiomeric purity.
Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Esters with Chiral Iridium N,P Ligand Complexes
作者:David H. Woodmansee、Marc-André Müller、Lars Tröndlin、Esther Hörmann、Andreas Pfaltz
DOI:10.1002/chem.201202397
日期:2012.10.22
Enantioselective conjugate reduction of a wide range of α,β‐unsaturated carboxylicesters was achieved using chiral Ir N,P complexes as hydrogenation catalysts. Depending on the substitution pattern of the substrate, different ligands perform best. α,β‐Unsaturated carboxylicesters substituted at the α position are less problematic substrates than originally anticipated and in some cases α‐substituted
and versatile approach to 1,2-diamines has been developed based on reductivecoupling reactions of various imines, where perylene, an aromatic hydrocarbon, was used as a photoredox catalyst under visiblelight irradiation using a white light-emitting diode. The use of 1 mol % perylene enabled almost complete conversion of the imines, leading to the formation of their corresponding 1,2-diamines, which
Diastereospecific Coupling of Imines by Low-Valent Titanium: An Experimental and Computational Study
作者:Akshai Kumar、Ashoka G. Samuelson
DOI:10.1002/ejoc.201001256
日期:2011.2
phenylsilane (PhSiH3) and titanium(IV) isopropoxide Ti(OiPr)(4)] generates low-valenttitanium alkoxides that reduce and reductively couple imines. The C-C coupling reaction is diastereospecific, with exclusive formation of the (+/-)-isomer. The yield is dependent on the concentration of titanium(IV) isopropoxide used. Using imines with varying electronic demand revealed that the coupling is most efficient