Do aromatic transition states lower barriers to silatropic shifts? A synthetic, NMR spectroscopic, and computational study

被引：0

作者：

Rigby, Suzie S. ^{[1
]}

Gupta, Hari K. ^{[1
]}

Werstiuk, Nick H. ^{[1
]}

Bain, Alex D. ^{[1
]}

McGlinchey, Michael J. ^{[1
]}

机构：

[1] Department of Chemistry, McMaster University, Hamilton, Ont. L8S 4M1, Canada

来源：

Inorganica Chimica Acta | 1996年 / 251卷 / 1-2 PART II期

基金：

加拿大自然科学与工程研究理事会;

关键词：

Computation theory - Polycyclic aromatic hydrocarbons - Silicon - Aromatization;

D O I：

10.1016/s0020-1693(96)05290-5

中图分类号：

学科分类号：

摘要：

In a previous calculational study at the semi-empirical unrestricted Hartree-Fock (UHF) level of theory, we predicted that strategically incorporating an aromatic ring onto indenyltrimethylsilane would lower the barrier for [1,5]-silatropic shifts around the five-membered ring through retention of aromatic character in the transition state and in the intermediate iso-indene. We now report the synthesis and dynamic behavior of the tricyclic system angular trimethylsilylbenzindene, and also the tetracycle trimethylsilylcyclopenta[l]phenanthrene. Incorporation of one aromatic ring onto the indenyl ligand does lower the ΔG≠ value for [1,5]-silatropic shifts to 21.9 ± 0.5 kcal mol-1, compared to 24 kcal mol-1 for the indenyl system. Addition of a second aromatic ring further lowers the barrier to 17.6 ± 0.2 kcal mol-1, in good agreement with calculations. The intermediate iso-indenes for both systems have been trapped as their Diels-Alder adducts with tetracyanoethylene.

引用

页码：355 / 364