Asymmetric ruthenium-catalyzed 1,4-additions of aryl thiols to enones
作者:Andrei Bădoiu、Gerald Bernardinelli、Céline Besnard、E. Peter Kündig
DOI:10.1039/b918877k
日期:——
bind and activate α,β-unsaturated carbonyl compounds for cycloadditionreactions. These mild Lewisacidscatalyzeasymmetric 1,4-addition reactions of aryl thiols to enones with product selectivities up to 87% ee. 31P NMR experiments provide an insight into the intricate equilibria governing the reaction mechanism. The absolute configuration of the major products indicates enones to react in the syn-s-trans
定义明确,稳定的单点绑定 钌配合物1和2选择性地结合并活化α,β-不饱和羰基化合物以进行环加成反应。这些温和的路易斯酸催化芳基硫醇与烯酮的不对称1,4-加成反应,产物选择性高达ee的87%。31 P NMR实验提供了控制反应机理的复杂平衡的见解。主要产品的绝对构型表示烯酮的反应合成- S ^ -反式方向。基于Ru配合物的X射线结构的模型可用于合理化选择性。
Direct Proline-Catalyzed Asymmetric α-Aminoxylation of Aldehydes and Ketones
The direct proline-catalyzedasymmetric α-aminoxylation of aldehydes and ketones has been developed using nitrosobenzene as an oxygen source, affording α-anilinoxy-aldehydes and -ketones with excellent enantioselectivity. Reaction conditions have been optimized, and low temperature (−20 °C) was found to be a key for the successful α-aminoxylation of aldehydes, while slow addition of nitrosobenzene
Interference of the Surface of the Solid on the Performance of Tethered Molecular Catalysts
作者:Junghyun Hong、Francisco Zaera
DOI:10.1021/ja304181q
日期:2012.8.8
observed upon tethering, which could be accounted for by a combination of at least three effects: (1) the nonselective catalytic activity of the surface of the solid itself; (2) the activity of the OH species generated by hydrolysis of some of the Si-alkoxy groups in the trialkoxy moieties used to bind many linkers to oxide surfaces; and (3) the bonding of the molecule to be tethered directly to the surface
Asymmetric Induction in the Base-Catalyzed Reactions Using Polymer-Supported Quinines with Spacer Groups
作者:Minoru Inagaki、Jun Hiratake、Yukio Yamamoto、Jun’ichi Oda
DOI:10.1246/bcsj.60.4121
日期:1987.11
New polymer-supported quinines having the spacer groups were synthesized and utilized for three types of base-catalyzed asymmetric reactions. Insertion of the spacer groups leads to improve the stereoselectivity in comparison with the polymer-catalyst with no spacer groups.
OPTICALLY ACTIVE ALPHA-AMINOOXYKETONE DERIVATIVES AND PROCESS FOR PRODUCTION THEREOF
申请人:Tokyo University of Science
公开号:EP1661885A1
公开(公告)日:2006-05-31
The corresponding α-aminooxy ketone is manufactured with a high yield and a high enantioselectivity. A manufacturing method for an optically active α-aminooxy ketone derivative expressed by formula (1), wherein a ketone expressed by formula (2) is caused to react with a nitroso compound expressed by formula (3) in the presence of a proline derivative expressed by formula (4).
In the formula, R1 and R2 respectively denote an alkyl, alkenyl or alkynyl group, and R1 and R2 may be linked to form a ring. R3 denotes an aryl, heterocyclic, alkyl, alkenyl or alkynyl group. A denotes a hydrogen atom, alkoxy group, aryloxy group, acyloxy group or silyloxy group which may have a substituent.