Catalyzed asymmetric aryl transfer reactions to aldehydes with boroxines as aryl source
作者:Xiaoyu Wu、Xinyuan Liu、Gang Zhao
DOI:10.1016/j.tetasy.2005.06.010
日期:2005.7
Asymmetricaryltransfer of triphenylboroxin to a set of arylaldehydes has been carried out in the presence of chiral amino alcohols derived from (S)-proline with high enantioselectivity. Substituted phenyl boroxins were also used as arylsource in asymmetric arylation of benzaldehyde.
Synthesis of modular thiophene-oxazoline ligands and their application in the asymmetric phenyl transfer reaction to aldehydes
作者:Zhuo Chai、Xin-Yuan Liu、Xiao-Yu Wu、Gang Zhao
DOI:10.1016/j.tetasy.2006.09.004
日期:2006.9
A series of thiophene mono (oxazoline) N,O-ligands with three sites of diversity were synthesized concisely in two steps from the corresponding thiophene carbonitriles. These ligands were applied to the enantioselective phenyl transfer reaction of aldehydes, resulting in the corresponding chiral diaryl methanol products with excellent yields and moderate to good enantioselectivities.
The use of a chiral (NCP)Ir complex as the precatalyst allowed for the discovery of asymmetrictransferhydrogenation of diaryl ketones with ethanol as the hydrogen source and solvent. This reaction was applicable to various ortho-substituted diaryl keontes, affording benzhydrols in good yields and enantioselectivities. This protocol could be carried out in a gram scale under mild reaction conditions
使用手性 (NCP)Ir 配合物作为预催化剂,可以发现以乙醇为氢源和溶剂的二芳基酮的不对称转移氢化。该反应适用于各种邻位取代的二芳基酮,以良好的收率和对映选择性提供苯甲醇。该方案可以在温和的反应条件下以克级进行。通过合成 ( S )-新苯诺定的关键前体突出了催化体系的实用性。
Preparative synthesis of optically pure ortho-substituted benzhydrols by asymmetric reductions of the corresponding benzophenones
作者:Eric Brown、Antoine Lézé、Joël Touet
DOI:10.1016/s0957-4166(00)82179-5
日期:1992.7
Lithium aluminium hydride previously treated with 2.5 equivalents of (S)-(+) or (R)-(-)-2 -(2-iso-indolinyl)butan-1-ol 3 (readily available reagents) reduced the five ortho-substituted benzophenones 4-6, 8 and 10 into the corresponding optically active benzhydrols with nearly 100% enantiomeric excesses. Other examples of asymmetric reductions of prochiral benzophenones are given.
Axially chiral C2-symmetric N-heterocyclic carbene (NHC) palladium complexes-catalyzed asymmetric arylation of aldehydes with arylboronic acids
作者:Rui Zhang、Qin Xu、Xiuchun Zhang、Tao Zhang、Min Shi
DOI:10.1016/j.tetasy.2010.06.041
日期:2010.8
Chiral C-2-symmetric N-heterocyclic carbene (NHC) palladium diaquo complexes 5a-c and the chiral C-2-symmetric NHC-palladium complexes 5d and 5e prepared from (R)-BINAM or H-8-(R)-BINAM could be used as the catalysts for the enantioselective arylation of arylaldehydes with arylboronic acids in which NHC-Pd complex 5a was found to be fairly effective in this reaction to give the corresponding adducts in moderate enantioselectivities along with moderate to good yields. (C) 2010 Elsevier Ltd. All rights reserved.