described by the linear free energy relationship log k2 (20 °C) = sN(N + E), where N and sN are solvent-dependent nucleophile-specific parameters, and E is an electrophile-specific parameter. The electrophilicity parameters E of the investigated acceptor-substituted alkenes were derived from the linear correlations of (log k2)/sN vs. N, and range from –19.8 to –11.1.
在 DMSO 中,在 20 °C 下研究了马来酸酐、N-甲基马来酰亚胺、富马腈、富马酸二乙酯和马来酸二乙酯与吡啶鎓和锍叶立德的反应动力学。发现所有反应都遵循二阶速率定律,可以通过线性自由能关系 log k2 (20 °C) = sN(N + E) 来描述,其中 N 和 sN 是溶剂依赖性亲核试剂 -特定参数,E 是亲电试剂特定参数。所研究的受体取代烯烃的亲电性参数 E 源自 (log k2)/sN 与 N 的线性相关性,范围从 –19.8 到 –11.1。
STEREOSELECTIVE HYDROALKYLIDENATION OF OLEFIN WITH PYRIDINIUM METHYLIDES
Acid-catalyzed elimination of pyridine from the stereoselective [3+2] cycloadducts between electron-deficient olefins and pyridinium methylides with ylide-stabilizing substituents offers a new type of C–C bond formation.
Use of Polymer-Supported 4-(N,N-Dimethylamino)pyridine in a Formal Conjugate Addition/Elimination Mediated by an N-Ylide Generated In Situ for the Construction of Highly Functionalized Itaconimides/Alkenes
作者:Suman K. Saha、Anshul Jain、Nirmal K. Rana、Akanksha Kumari、Tshering Sangmo Bhutia、Chanchal Agrawat
DOI:10.1055/a-1934-1189
日期:2023.4
[3+2]-cycloadducts from a pyridinium ylide generated in situ from polymer-bound DMAP (PS-DMAP) with an N-substituted maleimide or an α,β-unsaturated β-keto ester. The cycloadduct decomposes to regenerate supported DMAP and yield a functionalized itaconimide or olefin. The method has a broad substrate scope. The alkene product has been further transformed into trisubstituted furan. PS-DMAP could be reused