作者:Thomas Xaver Gentner、Gerd Ballmann、Jürgen Pahl、Holger Elsen、Sjoerd Harder
DOI:10.1021/acs.organomet.8b00572
日期:2018.12.10
clean and gave a precipitate of the product in which the MeNHO ligand is cleanly lithiated in the alkene backbone (1). Lithiation of the much bulkier 1,3-bis(2,6-di-iso-propylphenyl)-2-methyleneimidazole (DIPPNHO) needs the presence of TMEDA as a cosolvent to give backbone lithiation (2). Depending on the cosolvent, the following products could be crystallized and fully characterized by X-ray diffraction
n BuLi在己烷/苯中对1,3-二甲基-2-亚甲基咪唑(Me NHO)进行质子交换快速而干净,得到的产物沉淀是Me NHO配体在烯烃主链中干净地被锂化(1)。备受笨重1,3-双(2,6-二-锂化异-propylphenyl)-2- methyleneimidazole(DIPP NHO)需要TMEDA的存在作为助溶剂,得到主链锂化(2)。根据助溶剂的不同,以下产物可能会结晶并通过X射线衍射和NMR进行全面表征:1-THF,1-TMEDA,1-(TMEDA)0.5和2-TMEDA。具有饱和主链的Me NHO配体不易被n BuLi锂化,甚至在高温下也不发生反应。然而,加入TMEDA已经在室温下通过开环产生了分解,从而给出了由二锂化的配体片段和两个锂化的TMEDA配体组成的复合聚集体。DFT计算揭示了环状C–N键之一断裂的可能机理。该过程最有可能经历饱和主链的事先锂化,似乎对于具有饱和主链的N