Expedient Access to Normal- and Abnormal- N-Heterocyclic Carbene (NHC) Magnesium Compounds from Imidazolium Salts
作者:Rajendra S. Ghadwal、Dennis Rottschäfer、Christian J. Schürmann
DOI:10.1002/zaac.201600308
日期:2016.11
] is prepared by the treatment of a C2-arylated imidazolium salt (IPrPh)I (5) with MeMgI. While the deprotonation of 1 and 2 can be accomplished at room temperature, an elevated temperature is required to deprotonate 5 with MeMgI. This is most likely due to the higher pKa value of the C4-H than that of the C2-H hydrogen atom. Salt metathesis reaction of 6 with KN(SiMe3)2 cleanly leads to the formation
用 MeMgI 处理咪唑鎓盐 (IPrH)Cl (1) 和 (IPrH)I (2) 导致形成正态 N-杂环卡宾 (nNHC) 化合物 (IPr)MgCl(I) (3) 和 (IPr)MgI2 (4) [IPr = 1,3-双(2,6-二异丙基苯基)咪唑-2-亚基]。通过采用类似的策略,第一个镁化合物 (aIPrPh)MgI2(OEt2) (6) 具有异常-NHC [aIPrPh = 1,3-双(2,6-二异丙基苯基)-2-苯基-咪唑-4-亚基] 是通过用 MeMgI 处理 C2-芳基化咪唑鎓盐 (IPrPh)I (5) 制备的。虽然 1 和 2 的去质子化可以在室温下完成,但需要升高温度才能用 MeMgI 去质子化 5。这很可能是由于 C4-H 的 pKa 值高于 C2-H 氢原子的 pKa 值。6 与 KN(SiMe3)2 的盐复分解反应完全导致形成氨基镁衍生物 (aIPrPh)MgN(SiMe3)2}2