在本文中,作者报告了 1-吡啶基-2-芳基乙烯、1-呋喃基-2-芳基乙烯、1,2-二苯基丙烯和取代的肉桂基苯胺作为类二苯乙烯的模型化合物,以研究主导取代基推挽效应的因素通过使用桥键碳原子的核磁共振化学位移。证明了最大推挽效应并不总是在 D-π-A 化合物中的强给电子 D 和强电子接受 A 基团之间。D-π-A化合物中取代基推挽作用的作用方式主要由其分子母体结构决定。组的场/感应效应和共轭效应对推挽效应的贡献是不相等的。当 D-π-A 母体分子在一个平面上时,组的场/感应效应对推挽效应的影响大于或接近其共轭效应的影响。虽然母体分子是空间扭曲的,但推挽效应主要取决于基团的共轭效应。本文的结果可以为我们提供关于取代基推拉效应的新见解。
Palladium-Catalyzed Stereoselective Synthesis of (E)-Stilbenes via Organozinc Reagents and Carbonyl Compounds
作者:Jin-Xian Wang、Kehu Wang、Lianbiao Zhao、Hongxia Li、Ying Fu、Yulai Hu
DOI:10.1002/adsc.200606016
日期:——
In the presence of a catalytic amount of PdCl2(PPh3)2 and a silylating agent, organozinc halides reacted with carbonylcompounds to give the corresponding (E)-stilbenes in good to excellent yields under mild conditions. The reaction mechanism is briefly discussed.
Doubly Regioselective C–H Hydroarylation of Unsymmetrical Alkynes Using Carboxylates as Deciduous Directing Groups
作者:Agostino Biafora、Bilal A. Khan、Janet Bahri、Joachim M. Hewer、Lukas J. Goossen
DOI:10.1021/acs.orglett.7b00300
日期:2017.3.3
carbonate, and mesitoic acid efficiently promotes the doubly regioselectiveC–H hydroarylation of unsymmetrical alkynes. The process involves carboxylate-directed ortho-C–H bond activation followed by regioselective addition to the alkyne C–C triple bond with concerted decarboxylation. This action of the carboxylate as a deciduous directing group ensures exclusive monovinylation with high selectivity
由[(C 6 Me 6)RuCl 2 ] 2,碳酸钾/碳酸胍和甲基磺酸组成的催化剂体系有效地促进了不对称炔烃的双区域选择性C–H加氢芳基化。该过程涉及羧基定向的邻-C-H键活化,然后区域选择性地添加到炔烃C-C三键中,并伴有协同的脱羧作用。羧酸盐作为落叶指导基团的这种作用确保了对(E)-1,2-二芳基烯烃具有高选择性的排他性单乙烯基化。
Synthesis of α-methylstilbenes using an aqueous Wittig methodology and application toward the development of potent human aromatase inhibitors
作者:Alexander J. Nielsen、Sergio Raez-Villanueva、Denis J. Crankshaw、Alison C. Holloway、James McNulty
DOI:10.1016/j.bmcl.2019.03.033
日期:2019.6
styrenes. Application of the α-methylstilbenes toward the synthesis of a collection of stilbenoid-triazoles is reported and their inhibition of CYP450 19A1 (aromatase) investigated. The overall structure-activity profile provided additional evidence on the aryl halide-ketone bioisostere hypothesis and identified 6c as a potent inhibitor of aromatase in vitro (Ki = 8 nM).
The first transition metal-free highly stereoselective positional isomerization of various α-alkyl styrenes through a carbocation mechanism triggered strategy is developed by using Al(OTf)3 as a hidden Brønsted acid catalyst, which provides facile access to value-added acyclic tri- and tetra-substituted alkenes in good yields with high stereoselectivity under mild conditions. The practicality of this
Rh-catalyzed addition of boronic acids to alkynes for the synthesis of trisubstituted alkenes in a biphasic system - Mechanistic study and recycling of the Rh/m-TPPTC catalyst
The versatilepreparation of trisubstituted alkenes via selective Rh-catalyzed arylation of alkynes is described in water and in a water/toluene biphasic system. For hydrophobic alkyl alkynes, the reaction afforded either alkenes or dienes depending on the temperature and the solvent conditions. Aryl, heteroaryl, silylated and alkyl substituted alkynes reacted equally well with various boronic acids