新型氮杂环卡宾-铱（I）配合物及其在未活化氨基烯烃分子内氢胺化反应中的应用
Unusual NHC-Iridium(I) Complexes and Their Use in the Intramolecular Hydroamination of Unactivated Aminoalkenes.
作者信息
Sipos Gellért, Ou Arnold, Skelton Brian W, Falivene Laura, Cavallo Luigi, Dorta Reto
机构信息
School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia.
Centre for Microscopy, Characterisation and Analysis, University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia.
出版信息
Chemistry. 2016 May 10;22(20):6939-46. doi: 10.1002/chem.201600378. Epub 2016 Apr 5.
N-heterocyclic carbene (NHC) ligands with naphthyl side chains were employed for the synthesis of unsaturated, yet isolable (NHC)Ir(cod) (cod=1,5-cyclooctadiene) complexes. These compounds are stabilised by an interaction of the aromatic wingtip that leads to a sideways tilt of the NHC-Ir bond. Detailed studies show how the tilting of such N-heterocyclic carbenes affects the electronic shielding properties of the carbene carbon atom and how this is reflected by significant upfield shifts in the (13) C NMR signals. When employed in the intramolecular hydroamination, these (NHC)Ir(cod) species show very high catalytic activity under mild reaction conditions. An enantiopure version of the catalyst system produces pyrrolidines with excellent enantioselectivities.
带有萘基侧链的N-杂环卡宾（NHC）配体被用于合成不饱和但可分离的[(NHC)Ir(cod)]⁺（cod = 1,5-环辛二烯）配合物。这些化合物通过芳香翼尖的相互作用得以稳定，这种相互作用导致NHC-Ir键发生侧向倾斜。详细研究表明，此类N-杂环卡宾的倾斜如何影响卡宾碳原子的电子屏蔽性质，以及这如何在¹³C NMR信号中显著的高场位移中得到体现。当用于分子内氢胺化反应时，这些[(NHC)Ir(cod)]⁺物种在温和的反应条件下表现出非常高的催化活性。该催化剂体系的对映纯形式能以优异的对映选择性生成吡咯烷。
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