empirical nucleophilicity parameter, and s is a nucleophile-specific slope parameter. From plots of log k versus E of the benzhydrylium ions are derived the solventnucleophilicity parameters s and N, the latter of which are designated as N1 to emphasize that their use in the quoted correlation equation gives rise to first-order rate constants. A linear correlation between N1 and Kevill's solvent nucleophilicity
二苯甲基鎓离子(二芳基碳鎓离子)与不同组成的溶剂混合物(水/乙腈、甲醇/乙腈、乙醇/乙腈、乙醇/水和三氟乙醇/水)的反应速率已通过常规紫外-可见光谱法测定、停流方法和激光闪光技术。已经表明,一阶速率常数遵循先前公布的关系 log k(20°C) = s(N + E),其中 E 是经验亲电性参数,N 是经验亲核性参数,s 是亲核试剂特异性斜率参数。从二苯鎓离子的 log k 与 E 的关系图推导出溶剂亲核性参数 s 和 N,后者被指定为 N1 以强调它们在引用的相关方程中的使用会产生一阶速率常数。报告了 N1 和基于 S-甲基二苯并噻吩鎓离子的 Kevill 溶剂亲核性 NT 之间的线性相关性,这允许将两组数据相互转换。由于 N1 值与之前报道的 pi 系统 (www.cup.uni-muenchen.de/oc/mayr/) 的亲核参数 N 直接相当,因此具有溶剂分解生成的碳正离子的 Friedel-Crafts
Villiger; Kopetschni, Chemische Berichte, 1912, vol. 45, p. 2920
作者:Villiger、Kopetschni
DOI:——
日期:——
Stereoselective Alkylation of (<i>S</i>)-<i>N</i>-Acyl-4-isopropyl-1,3-thiazolidine-2-thiones Catalyzed by (Me<sub>3</sub>P)<sub>2</sub>NiCl<sub>2</sub>
作者:Javier Fernández-Valparís、Juan Manuel Romo、Pedro Romea、Fèlix Urpí、Hubert Kowalski、Mercè Font-Bardia
DOI:10.1021/acs.orglett.5b01626
日期:2015.7.17
The structurally simple (Me3P)(2)NiCl2 complex catalyzes S(N)1-type alkylations of chiral N-acyl thiazolidinethiones with diarylmethyl methyl ethers and other stable carbenium cations. The former can contain a variety of functional groups and heteroatoms at the alpha-position. The resultant adducts are isolated as single diastereomers in high yields and can be converted into enantiomerically pure derivatives in a straightforward manner.