Synthesis of Optically Active 2-Chloromethyl-2-oxazolines by the Ortho-ester Codensation Method Using Triethyl Orthochloroacetate
摘要:
A set of optically active 2-chloromethyl-2-oxazolines was synthesized by condensation of optically active 2-amino alcohols with triethyl orthochloroacetate which was prepared conveniently from triethyl orthoacetate by chlorination using tert-butyl hypochlorite.
Asymmetric Hydrogenation of Unfunctionalized Tetrasubstituted Acyclic Olefins
作者:Raphael Bigler、Kyle A. Mack、Jeff Shen、Paolo Tosatti、Chong Han、Stephan Bachmann、Haiming Zhang、Michelangelo Scalone、Andreas Pfaltz、Scott E. Denmark、Stefan Hildbrand、Francis Gosselin
DOI:10.1002/anie.201912640
日期:2020.2.10
Asymmetrichydrogenation has evolved as one of the most powerful tools to construct stereocenters. However, the asymmetrichydrogenation of unfunctionalized tetrasubstituted acyclic olefins remains the pinnacle of asymmetric synthesis and an unsolved challenge. We report herein the discovery of an iridium catalyst for the first, generally applicable, highly enantio- and diastereoselective hydrogenation
Imidazolium‐Oxazoline Salts in Ruthenium‐Catalyzed Allylic Substitution and Cross Metathesis of Formed Branched Isomers
作者:Hamed Ben Ammar、Bechir Ben Hassine、Cédric Fischmeister、Pierre H. Dixneuf、Christian Bruneau
DOI:10.1002/ejic.201000718
日期:2010.10
Imidazolium-oxazoline chlorides have been prepared from chloroacetonitrile and used to generate bidentate mixed NHC-oxazoline ligands for ruthenium-catalyzed substitution of cinnamylchloride by phenols. These ligands associated to [RuCp*(MeCN)3][PF6] promote allylic substitution reactions at room temperature with high regioselectivity in favour of the branched isomers giving terminal alkenes. These allylic ethers
designed and synthesized a new bisoxazoline‐imidazolium salt as a carbene precursor, which owns three chelating sites and two kinds of chiral information. A preliminary investigation of asymmetricketonereduction was also studied.