Biomimetic Photocycloaddition of 3-Hydroxyflavones: Synthesis and Evaluation of Rocaglate Derivatives as Inhibitors of Eukaryotic Translation
作者:Stéphane P. Roche、Regina Cencic、Jerry Pelletier、John A. Porco
DOI:10.1002/anie.201003212
日期:2010.9.3
Shedding light on translation: A light‐driven, biomimetic [3+2] cycloaddition has been achieved with the synthesis of a series of rocaglate derivatives. Mechanistic data suggest the possibility for donor–acceptor interactions and the involvement of triplet biradicaloids in the photoexcited state. Several new rocaglate derivatives approach the potency of the anticancer agent silvestrol.
Polymerization of Acrylates by Neutral Palladium Complexes. Isolation of Complexes at the Initial Steps
作者:Ana C. Albéniz、Pablo Espinet、Raquel López-Fernández
DOI:10.1021/om030507t
日期:2003.10.1
initiated by small amounts of the radicals generated from these complexes (5, 6, or 9). Formation of 9 is the regeneration pathway of radicals after a termination reaction has occurred by recombination of the growing radical with palladium and β-H elimination. The success of the polymerization requires a slow but steady supply of radicals by slow decomposition of alkylcomplexes (5 and 6) or by slow generation
五氟苯基配合物[Pd 2(μ-X)2(C 6 F 5)2 L 2 ](L =四氢噻吩(tht),X = Cl,2; L = tht,X = Br,3)聚合丙烯酸甲酯; L = AsPh 3,X = Br,4)以良好的产率得到无规立构聚合物。机理研究表明,丙烯酸甲酯的聚合反应开始于将丙烯酸甲酯插入预催化剂的Pd-芳基键中,从而得到烷基络合物反式-[Pd 2(μ-Cl)2 CH(CO 2 Me)-CH 2 C 6楼5 } 2(tht)2 ](5)和反式-[Pd 2(μ-Cl)2 CH(C 6 F 5)CH 2 CO 2 Me} 2(tht)2 ](6)。可以分离这些络合物,并且已经确定了5的X射线晶体结构。配合物5和6主要通过消除β-H分解,也可以通过在光中Pd-C键的均相裂解而分解。在丙烯酸甲酯的存在下,MA在氢化-Pd物种中的插入会生成烷基复合物反式-[Pd2(μ-Cl)2 CH(CO