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。
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).
Hf(OTf)<sub>4</sub>-Catalyzed 1,6-Conjugate Addition of 2-Alkyl-azaarenes to <i>para</i>-Quinone Methides
作者:Xinyuan Liu、Binbin Liu、Zhan Shi、Chen Tan、Rong Fan、Zhi Li、Jiajing Tan
DOI:10.1021/acs.joc.0c02982
日期:2021.2.19
Herein we reported a Hf(OTf)4-catalyzed carbon–carbonbondformation reaction between 2-alkyl-azaarenes and para-quinone methides (p-QMs). This 1,6-conjugate addition protocol offered rapid access to a large array of triarylethane products in good yields. The catalyst loading could be reduced to 1 mol %. Studies pertinent to scale-up reaction and product derivatization were also presented.
Metal-free, Tf2NH-catalyzed 1, 6-conjugate addition of imidazopyridine to para-quinone methides: Easy access to C3-functionalized triarylmethane imidazopyridine
作者:Nilesh S. Khonde、Madhukar S. Said、Jagjivan K. Sabane、Jayant M. Gajbhiye、Pradeep Kumar
DOI:10.1016/j.tet.2021.132510
日期:2021.11
An inexpensive and commercially available Tf2NH-catalyzed 1,6-conjugate addition of imidazopyridine (IMPY) heterocycles to para-quinone methides (p-QMs) is reported. The present transformation provides a diverse class of C3-functionalized triarylmethanes heterocyclic derivatives of imidazopyridine. These metal-free transformations provided a very broad substrate scope of conjugate addition product