Application of a Heterogeneous Chiral Titanium Catalyst Derived from Silica-Supported 3-Aryl H<sub>8</sub>-BINOL to Enantioselective Alkylation and Arylation of Aldehydes
derivative as a precursor, and the resulting silica-supported ligand (6 mol %) was employed in the enantioselectivealkylation and arylation of aldehydes in the presence of Ti(OiPr)4. The reactions using Et2Zn, Et3B, and aryl Grignard reagents all afforded the corresponding adducts in high enantioselectivities and yields. The silica-immobilized titanium catalyst could be reused up to 14 times without appreciable
Synthesis of Planar Chiral [2.2]Paracyclophanyl Imidazo[1,5-<i>a</i>]pyridinium Salts for the Rhodium-Catalyzed Asymmetric Arylation
作者:Dengxia Wang、Yudao Ma、Fuyan He、Wenzeng Duan、Lei Zhao、Chun Song
DOI:10.1080/00397911.2011.610548
日期:2013.2.1
Abstract Several novel flexibility-restricted imidazo[1,5-a]pyridinium triflates (abbreviated as imidazolium salts) were synthesized from (4S p,13R p)-(−)-4-amino-13-bromo[2.2]paracyclophane and pyridylaldehyde. These imidazolium salts can be used as nitrogen-containing heterocyclic carbene precursors in asymmetric catalysis and here they are applied in the Rh-catalyzed asymmetric 1,2-addition of arylboronic
Asymmetric Synthesis of Diarylmethanols by Rh(I)-Catalyzed Arylation of Aromatic Aldehydes with Arylboronic Acid
作者:Kazuhiro Kondo、Toyohiko Aoyama、Kiyoto Suzuki
DOI:10.1055/s-2006-926391
日期:2006.4
Asymmetric synthesis of diarylmethanols by Rh(I)-catalyzedarylation of aromatic aldehydes with arylboronicacids, is described. A catalyst comprised of [RhCl(coe) 2 ] 2 and i-Pr-DuPHOS affords diarylmethanols with up to 66% ee. To the best of our knowledge this is the best enantioselectivity reported for Rh-catalyzed arylation of aldehydes.
Nickel-catalyzed 1,2-addition of arylboroxines to aromatic aldehydes
作者:Takafumi Arao、Kazuhiro Kondo、Toyohiko Aoyama
DOI:10.1016/j.tetlet.2007.04.025
日期:2007.6
Development of Ni-Et-Duphos-catalyzed 1,2-addition of arylboroxines to aromatic aldehydes is described. The dramatic effect of boron reagent and phosphine ligand is observed. This method with a phosphine ligand allows asymmetric arylation of aromatic aldehydes (up to 78% ee). (c) 2007 Elsevier Ltd. All rights reserved.
Synthesis of new alkoxy/sulfonate-substituted carbene precursors derived from [2.2]paracyclophane and their application in the asymmetric arylation of aldehydes
作者:Wenzeng Duan、Yudao Ma、Bo Qu、Lei Zhao、Jianqiang Chen、Chun Song
DOI:10.1016/j.tetasy.2012.09.001
日期:2012.10
A series of novel planar chiral alkoxy/sulfonate-substituted carbene precursors have been designed and synthesized. They were used as N-heterocyclic carbene ligands in the Rh-catalyzed asymmetric addition of arylboronic acids to aromatic aldehydes, affording chiral diarylmethanols with high yields and moderate enantioselectivities. (C) 2012 Elsevier Ltd. All rights reserved.