Recyclable Bismuth Complex Catalyzed 1,6-Conjugate Addition of Various Nucleophiles to <i>para</i>
-Quinone Methides: Expedient Access to Unsymmetrical Diaryl- and Triarylmethanes
作者:Xianghao Liang、Haiyan Xu、Hanlin Li、Lizhuang Chen、Hongfei Lu
DOI:10.1002/ejoc.201901732
日期:2020.1.16
An efficient method for the 1,6‐conjugateaddition of para‐quinonemethides with readily available nucleophiles was developed. This protocol provides straightforward access to a class of diaryl and triarylmethane derivatives with good to excellent yields in the presence of (C4H12N2)2[BiCl6]Cl·H2O. Moreover, this bismuth complex can be recycled for several times.
已开发出一种有效的方法,可将1,6-共轭对苯二甲酰甲基与易得的亲核试剂加在一起。在(C 4 H 12 N 2)2 [BiCl 6 ] Cl · H 2 O存在下,该方案可以直接获得具有良好产率或优异产率的二芳基和三芳基甲烷衍生物。此外,该铋络合物可回收用于几次。
From Carbanions to Organometallic Compounds: Quantification of Metal Ion Effects on Nucleophilic Reactivities
The influence of the metal on the nucleophilic reactivities of indenyl metalcompounds was quantitatively determined by kinetic investigations of their reactions with benzhydrylium ions (Ar2CH+) and structurally related quinone methides. With the correlation equation log k2=sN(N+E), it can be derived that the ionic indenyl alkali compounds are 1018 to 1024 times more reactive (depending on the reference
金属对茚基金属化合物亲核反应性的影响是通过动力学研究其与二苯甲基鎓离子(Ar 2 CH +)和与结构相关的醌甲基化物的反应来定量确定的。利用相关方程log k 2 = s N(N + E),可以得出离子型茚基碱性化合物的反应性(取决于参考亲电试剂)是相应的茚基三甲基硅烷的10 18至10 24倍。
Quaternary β<sup>2,2</sup>-amino acid derivatives by asymmetric addition of isoxazolidin-5-ones to <i>para</i>-quinone methides
synthesis of a new class of densely functionalized β2,2-amino acidderivatives by reacting isoxazolidin-5-ones with para-quinone methides in the presence of chiral ammonium salt phase-transfer catalysts was developed. The reaction proceeds with exceptionally low catalyst loadings down to 20 ppm on gram scale and the utilization of the primary addition products towards further manipulations was demonstrated
Base-promoted 1,6-conjugate addition of alkylazaarenes to <i>para</i>-quinone methides
作者:Amritha Rayaroth、Rajat Kumar Singh、Kalyanakrishnan A. V.、Krishna Hari、Alagiri Kaliyamoorthy
DOI:10.1039/d0ob00419g
日期:——
1,1,2-Triarylethanes embedded with an azaarene unit were prepared in a single step at ambient temperature via the sodium hexamethyldisilazide mediated 1,6-conjugate addition of unactivated alkylazaarenes on para-quinone methides (p-QMs).
The kinetics of the reactions of different heterocyclic anions derived from imidazoles, purines, pyrimidines, and related compounds with benzhydrylium ions and structurally related quinone methides have been studied in DMSO and water. The second‐order rate constants (log k2) correlated linearly with the electrophilicity parameters E of the electrophiles according to the correlation log k2 = sN(N+E)