Synthesis and Reactivity of (C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>B−<i>N</i>-Heterocycle Complexes. 1. Generation of Highly Acidic sp<sup>3</sup> Carbons in Pyrroles and Indoles
作者:Simona Guidotti、Isabella Camurati、Francesca Focante、Luca Angellini、Gilberto Moscardi、Luigi Resconi、Rino Leardini、Daniele Nanni、Pierluigi Mercandelli、Angelo Sironi、Tiziana Beringhelli、Daniela Maggioni
DOI:10.1021/jo020647x
日期:2003.7.1
The reaction of pyrroles and indoles with B(C(6)F(5))(3) and BCl(3) produces 1:1 B-N complexes containing highly acidic sp(3) carbons, for example, N-[tris(pentafluorophenyl)borane]-5H-pyrrole (1) and N-[tris(pentafluorophenyl)borane]-3H-indole (2), that are formed by a new formal N-to-C hydrogen shift, the mechanism of which is discussed. With some derivatives, restricted rotation around the B-N bond
吡咯和吲哚与B(C(6)F(5))(3)和BCl(3)的反应产生1:1的BN络合物,其中含有高度酸性的sp(3)碳,例如N- [三(五氟苯基)硼烷] -5H-吡咯(1)和N- [三(五氟苯基)硼烷] -3H-吲哚(2),它们是由新的正式的N-C氢转移形成的,并讨论了其机理。对于某些衍生物,通过NMR技术观察到绕BN键和/或BC键的旋转受限制,并且从实验数据计算出一些旋转势垒。这些复合物中sp(3)碳的酸度通过质子化NEt(3)以及形成吡咯基-和吲哚基-硼酸铵盐来表明。该反应的驱动力是由杂环的芳香性的恢复给出的。