Organocatalytic Tandem Three-Component Reaction of Imine, Alkyl Vinyl Ketone, and Imide via aza-Baylis−Hillman Reaction
作者:Siang-en Syu、Yu-Ting Lee、Yeong-Jiunn Jang、Wenwei Lin
DOI:10.1021/jo102143r
日期:2011.4.15
A highly chemoselective PPh3-catalyzed three-component reaction of an imine, alkyl vinyl ketone, and phthalimide or succinimide is developed. Various highly functional adducts with high diastereoselectivities can be generated via aza-Morita−Baylis−Hillman reactions of aryl-substituted imines and alkyl vinyl ketones followed by Michael additions of imides and then epimerization.
1,3,5-Triaza-7-phosphaadamantane (PTA): A Practical and Versatile Nucleophilic Phosphine Organocatalyst
作者:Xiaofang Tang、Bo Zhang、Zhengrong He、Ruili Gao、Zhengjie He
DOI:10.1002/adsc.200700071
日期:2007.8.6
cycloaddition reaction of 4-substituted 2,3-butadienoates with N-tosylimines, PTA is also proven to be a comparable catalyst as tributylphosphine (PBu3). By systematic comparison with other structurally similar N,P catalysts, it is concluded that the superiority of PTA in the above nucleophilic catalysis is attributable to its comparable nucleophilicity with that of trialkylphosphines. The feasibility
The aza-MoritaâBaylisâHillman (azaMBH) reaction has been studied for electronically and sterically deactivated Michael acceptors. It is found that electronically deactivated systems can be converted with electron-rich phosphanes and pyridines as catalysts equally well. For sterically deactivated systems clearly better catalytic turnover can be achieved with pyridine catalysts. This is in accordance with the calculated affinities of the catalysts towards different Michael-acceptors.
In the Baylis-Hillman reaction of N-benzylidene-4-methylbenzenesulfonamide with methylvinylketone (MVK), we found that, in the presence of a catlytic amount of DMAP, PPh^3 or DABCO as Lewis base, jthe Baylis-Hillman reaction can be greatly accelerated to give the normmal Baylis-Hillman adducts 1 in good or jvery jhigh yields. However, with Pbu^3 as a Lewis base, the abnormal Baylis-Hillman adducts
The aza‐Morita‐Baylis–Hillman (aza‐MBH) reaction has been studied in a variety of solvents, a selection of imine substrates and with various combinations of PPh3 and para‐nitrophenol as the catalyst system. The measured kinetic data indicates that the effects of solvent and protic co‐catalyst are strongly interdependent. These results are most easily reconciled with a mechanistic model involving the
已在多种溶剂,多种亚胺底物以及PPh 3和对硝基苯酚的各种组合作为催化剂体系中研究了aza-Morita-Baylis-Hillman(aza-MBH)反应。测得的动力学数据表明,溶剂和质子助催化剂的作用密切相关。这些结果最容易与涉及两性离子中间体在催化循环中可逆质子化的机理模型相吻合,这也得到31 P NMR光谱学和量子化学研究的支持。