Li Yanjun, Lei Meng, Yuan Wei, Meggers Eric, Gong Lei
College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China.
Chem Commun (Camb). 2017 Jul 13;53(57):8089-8092. doi: 10.1039/c7cc04691j.
A cyclometalating N-heterocyclic carbene iridium complex featuring metal-centered chirality was designed and used for the asymmetric transfer hydrogenation (ATH) of imines. Four strongly σ-donating carbon-based substituents (2 carbenes and 2 phenyl moieties), a chirality transfer directly from the stereogenic metal center to the C[double bond, length as m-dash]N bond of substrates, as well as a restriction of catalyst deactivation by steric demanding substituents, render the new complex one of the most efficient catalysts for ATH of cyclic N-sulfonylimines (down to 0.01 mol% cat., 24 examples, 94-98% ee).
设计了一种具有金属中心手性的环金属化N-杂环卡宾铱配合物，并将其用于亚胺的不对称转移氢化反应（ATH）。四个强σ供电子碳基取代基（2个卡宾和2个苯基部分），手性直接从立体中心金属中心转移到底物的C=N键上，以及通过空间位阻较大的取代基限制催化剂失活，使得这种新型配合物成为环状N-磺酰亚胺不对称转移氢化反应中最有效的催化剂之一（催化剂用量低至0.01 mol%，24个实例，对映体过量值为94-98%）。
