Truly Catalytic and Enantioselective Pinacol Coupling of Aryl Aldehydes Mediated by Chiral Ti(III) Complexes<sup>†</sup>
作者:A. Chatterjee、T. H. Bennur、N. N. Joshi
DOI:10.1021/jo0342875
日期:2003.7.1
A variety of chiral Ti(IV) complexes were reduced in situ with zinc in acetonitrile. The resulting chiral Ti(III) complexes were found to catalyze the pinacol coupling reaction stereoselectively. The best results were obtained from the Ti-SALEN complex, which was found to be an efficient catalyst at 10 mol % concentration. Various aromatic aldehydes were coupled to obtain chiral hydrobenzoin derivatives
Enantioselective Pinacol Coupling of Aryl Aldehydes Catalyzed by Chiral Salan−Mo(IV) Complexes
作者:Hongwei Yang、Hongsong Wang、Chengjian Zhu
DOI:10.1021/jo701842r
日期:2007.12.1
Reported herein is the asymmetricpinacolcoupling of aromatic aldehydes with chiral Salan−Mo(VI) dioxo complex as an effective precatalyst. Chiral diols were obtained with high diastereoselectivity and enantioselectivity up to 92/8 and 95%, respectively. The possible mechanism of the pinacolcoupling reaction with the catalytic system was investigated. The X-ray crystal structure of the precatalyst
A variety of novel hydroxyl-containing tetradentate bisoxazolines were successfully synthesized from natural l-serine and β-DDB. The applications of these ligands in the asymmetricpinacolcoupling of aromatic aldehydes revealed that the absoluteconfigurations of the resulting pinacols were entirely dominated by the axial chirality of the biphenyl component and that the bulky substituent adjacent
Stereoselective Synthesis of Optically Active Hydrobenzoins via Asymmetric Hydrogenation of Benzils with Ru(OTf)(TsDPEN)(η6-cymene) as the Pre-catalyst
作者:Xiaofei Huang、Naikai Li、Zhicong Geng、Fengfeng Pan、Xingwang Wang
DOI:10.1002/cjoc.201200393
日期:2012.8.14
Opticallyactivehydrobenzoins are very important building blocks for further derivation of biologically active complexes, natural products, and pharmaceutical compounds. In this paper, A practical approach has been developed for asymmetrichydrogenation of benzils with Ru(OTf)(TsDPEN)(η6‐cymene) as a pre‐catalyst in methanol. Therefore, a series of chiral hydrobenzoins was synthesized in good yields
The asymmetric pinacol coupling of aromatic aldehydes by chiral salan-vanadium complexes as effective catalysts is reported. Chiral 1,2-diols were obtained with high diastereoselectivities (up to 90/10) and moderate to high enantioselectivities (up to 82% ee). The possible mechanism of the pinacol coupling reaction is also discussed. (C) 2009 Elsevier B. V. All rights reserved.