Synthesis and Reduction of Sterically Encumbered Mesoionic Carbene-Stabilized Aryldihaloboranes
作者:Merle Arrowsmith、Julian Böhnke、Holger Braunschweig、Haopeng Gao、Marc-André Légaré、Valerie Paprocki、Jens Seufert
DOI:10.1002/chem.201700500
日期:2017.9.7
Sterically hindered, in situ generated 1,3,4-substituted 1,2,3-triazol-5-ylidene mesoionic carbenes (MICs) were employed to stabilize a number of aryl- and heteroaryldihaloboranes, as well as the first MIC-supported diborane. Reduction of borane adducts of the 1-(2,6-diisopropylphenyl)-3-methyl-4-tert-butyl-1,2,3-triazol-5-ylidene ligand with KC8 in non-coordinating solvents led to intramolecular C-H-
受位阻的原位生成的1,3,4-取代的1,2,3-三唑-5-亚甲基中离子碳烯(MIC)用于稳定许多芳基和杂芳基二卤硼烷以及第一个MIC负载的乙硼烷。在非配位溶剂中用KC8还原1-(2,6-二异丙基苯基)-3-甲基-4-叔丁基-1,2,3-三唑-5-亚甲基的硼烷加合物导致分子内CH-并且,在支持配体的异丙基残基上进行CC活化。DFT计算表明,这些活化反应中的每一个均经由亚硼烷基中间体的不同异构体进行。