Synthesis and Reactivity of <i>N</i>-Heterocycle-B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> Complexes. 3. Generation of <i>N</i>-Methylpyrrol-2-yl and <i>N</i>-Methylindol-2-yl Borate Zwitterions with Acidic sp<sup>3</sup> Carbons
作者:Francesca Focante、Isabella Camurati、Daniele Nanni、Rino Leardini、Luigi Resconi
DOI:10.1021/om0499308
日期:2004.10.1
1-methylindole (4), in which a C(α)−B bond and an acidic sp3 methylene carbon are formed in the heterocyclic part of the molecule. Both derivatives present a restricted rotation around the C(α)−B and/or B−C6F5 bonds, and their rotational barriers (13.8 and 14.8 kcal mol-1 for 3 and 4, respectively) were calculated from 1H NMR experimental data. A kinetic study of the reaction, carried out by following
N-甲基吡咯和N-甲基吲哚与B(C 6 F 5)3的化学计量反应产生两性离子物质2- [三(五氟苯基)硼烷] -5 H -1-甲基吡咯(3)和2- [三(五氟苯基)硼] )硼烷] -3 H -1-甲基吲哚(4),其中在分子的杂环部分形成C(α)-B键和酸性sp 3亚甲基碳。既衍生物呈现以C受限旋转(α)-B和/或B-C 6 ˚F 5个键,并且它们的旋转障碍(13.8和14.8千卡摩尔- 1为根据1 H NMR实验数据分别计算出3和4)。在反应动力学研究,通过以下通过NMR转换进行的,得到的速率常数的值(在298K在二氯甲烷中)的3×10 - 5,6×10 - 5中号- 1个小号- 1为3和4,分别。配合物3和4与三乙胺定量反应,得到相应的三乙铵盐5和6。两性离子络合物及其铵盐都是用于乙烯聚合的Ind 2 ZrMe 2的有效活化剂。