Enantioposition-Selective Copper-Catalyzed Azide–Alkyne Cycloaddition for Construction of Chiral Biaryl Derivatives
摘要:
A highly enantioposition-selective copper-catalyzed azidealkyne cycloaddition (CuAAC) of dialkynes bearing prochiral biaryls has been developed for the construction of 1,2,3-triazoles bearing axially chiral biaryl groups in up to 76% yield and up to 99% ee.
Analysis of Intramolecular Dynamic Processes in Enantiomeric Diaryl Atropisomers and Related Derivatives by2H NMR Spectroscopy in Polypeptide Liquid Crystals
作者:Olivier Lafon、Philippe Lesot、Chun-An Fan、Henri B. Kagan
DOI:10.1002/chem.200601284
日期:2007.4.27
shown that these polypeptide mesophases have no significant impact on the interconversion dynamics of these compounds. In contrast with the nematic thermotropic phases, Haller's equation cannot be used to predict the evolution of the quadrupolar splittings (Deltanu(Q) values), and hence the order parameters, versus T in the PBLG mesophases. For these particular lyotropic systems, it is shown that an
Two aspects of the desymmetrization of selected prochiral aromatic or vinylic dihalides: enantioselective halogen–lithium exchange and prochiral recognition in chiral liquid crystals
作者:Chun-An Fan、Benoît Ferber、Henri B. Kagan、Olivier Lafon、Philippe Lesot
DOI:10.1016/j.tetasy.2008.12.003
日期:2008.12
Several classes of prochiral dihalides have been identified as potential candidates for asymmetric halogen-lithium exchange. Bis-aryl compounds I and 2, 2,3-dibromonorbornadiene 3, and 1,2-diiodoferrocene 4 were prepared and used as substrates in the asymmetric halogen-lithium exchange reaction. The enantioselective mono-lithiation was achieved in good yields by various combinations of n-BuLi and chiral ligands. Enantioselectivities in the range of 20-35% ee have been detected for this new type of asymmetric synthesis. The prochiral compounds 3 and 4 were also dissolved in a chiral liquid crystal based on organic solutions of poly-gamma-benzyl-L-glutamate and analyzed using natural abundance deuterium 2D NMR spectroscopy. The spectroscopic discrimination of enantiotopic sites in these solutes has been observed and discussed from the point of view of orientational order. (C) 2008 Elsevier Ltd. All rights reserved.
Enantioposition-Selective Copper-Catalyzed Azide–Alkyne Cycloaddition for Construction of Chiral Biaryl Derivatives
作者:Takao Osako、Yasuhiro Uozumi
DOI:10.1021/ol502778j
日期:2014.11.21
A highly enantioposition-selective copper-catalyzed azidealkyne cycloaddition (CuAAC) of dialkynes bearing prochiral biaryls has been developed for the construction of 1,2,3-triazoles bearing axially chiral biaryl groups in up to 76% yield and up to 99% ee.
Palladium-Catalyzed Desymmetric Intermolecular C–N Coupling Enabled by a Chiral Monophosphine Ligand Derived from Anthracene Photodimer
The development of chiral ligands with privileged scaffolds plays an important role in transition-metal-catalyzed asymmetric reactions. Herein we present anthracene-photodimer-derived chiral monophosphine ligand 1, which features dual chirality and a rigid scaffold. This ligand exhibits remarkable efficiency in Pd-catalyzed desymmetric intermolecular C–N coupling under mild conditions with excellent