Metal and halogen dependence of the rate effect in hydroamination/cyclization of unactivated aminoalkenes: Synthesis, characterization, and catalytic rates of CCC-NHC hafnium and zirconium pincer complexes
作者:Wesley D. Clark、Joon Cho、Henry U. Valle、T. Keith Hollis、Edward J. Valente
DOI:10.1016/j.jorganchem.2013.11.001
日期:2014.2
(2c) was reacted with a stoichiometric amount of Zr(NMe2)4 or Hf(NMe2)4 yielding four new early transition metal CCC-N-heterocylic carbene (CCC-NHC) pincer complexes. Two of the CCC-NHC pincer complexes were synthesized via a new methodology, which allowed for a room temperature reaction, shorter reaction times, and slightly less Zr(NMe2)4 or Hf(NMe2)4. The molecular structure of 2-(1,3-bis-3′-butyl
使1,3-双(3'-丁基咪唑-1'-基)苯二溴化物(2b)或1,3-双(3'-丁基咪唑-1'-基)苯二氯化物(2c)反应Zr(NMe 2)4或Hf(NMe 2)4产生四个新的早期过渡金属CCC- N-杂环卡宾(CCC-NHC)钳形配合物。通过一种新方法合成了两种CCC-NHC钳形复合物,该复合物可实现室温反应,更短的反应时间以及略微更少的Zr(NMe 2)4或Hf(NMe 2)4。通过X射线晶体学测定了2-(1,3-双-3'-丁基咪唑-1'-基-2'-亚苯基)亚苯基)(二甲基氨基)(二溴)锆(IV)(3b)的分子结构。评价该复合物用于未活化的氨基烯烃的加氢胺化/环化,产生吡咯烷或哌啶。加氢胺化/环化速率取决于配合物中的卤素或金属。具有碘化物配体的配合物给出了最快的加氢胺化/环化速率(I> Br> Cl)。Zr配合物比Hf类似物提供更快的加氢胺化/环化速率。CCC-NHC ZrI 3络合物5的使用提高了反应速率。