Understanding the Subtleties of Frustrated Lewis Pair Activation of Carbonyl Compounds by N-Heterocyclic Carbene/Alkyl Gallium Pairings
作者:Marina Uzelac、David R. Armstrong、Alan R. Kennedy、Eva Hevia
DOI:10.1002/chem.201603597
日期:2016.10.24
any of the carbonyl‐containing substrates included in this study NMR spectroscopic studies of the new compounds point to complex equilibria involving the formation of kinetic and thermodynamic species as implicated through DFT calculations. Extension to ketones proved successful for electrophilic α,α,α‐trifluoroacetophenone, yielding [aItBuC(Ph)(CF3)OGaR3] (7). However, in the case of ketones and nitriles
这项研究报告了将含有空间要求的单甲硅烷基的三烷基镓GaR 3(R = CH 2 SiMe 3)与疏松的N-杂环卡宾联用作为有效的Lewis酸组分来抑制羰基化合物的Lewis对活化的作用1,3-双(叔丁基)咪唑-2-亚基(I t Bu)或1,3-双(叔丁基)咪唑啉-2-亚基(SI t Bu)。醛的还原可通过在提供两性离子产物[I t BuCH 2 OGaR 3 ](1)或[I ]的卡宾的C2(所谓的正常)位置插入C = O官能团来实现。吨布赫(p -Br-C 6 H ^ 4)OGaR 3 ](2),或者可替换地,在它的异常(C4)的网站得到[一个我吨布赫(p -Br-C 6 H ^ 4)OGaR 3 ](3)。作为这两个部分的协同行为的证据,I t Bu和GaR 3,这两个化合物都无法单独激活本研究中包含的任何含羰基的底物。新化合物的NMR光谱研究表明,复杂的平衡涉及DFT计算所涉及的动力学