Center for Catalysis Research & Innovation, and Department of Chemistry and Biomolecular Sciences, University of Ottawa , Ottawa, Canada K1N 6N5.
X-Ray Crystallography Laboratory, University of Alberta , Edmonton, Canada T6G 2G2.
J Am Chem Soc. 2018 Feb 7;140(5):1604-1607. doi: 10.1021/jacs.7b13257. Epub 2018 Jan 24.
Ring-closing metathesis (RCM) offers versatile catalytic routes to macrocycles, with applications ranging from perfumery to production of antiviral drugs. Unwanted oligomerization, however, is a long-standing challenge. Oligomers can be converted into the cyclic targets by catalysts that are sufficiently reactive to promote backbiting (e.g., Ru complexes of N-heterocyclic carbenes; NHCs), but catalyst decomposition limits yields and selectivity. Incorporation of a hemilabile o-dianiline (ODA) chelate into new catalysts of the form RuCl(NHC)(ODA)(=CHPh) accelerates macrocyclization, particularly for dienes bearing polar sites capable of H-bonding: it may also inhibit catalyst decomposition during metathesis. Significant improvements relative to prior Ru-NHC catalysts result, with fast macrocyclization of conformationally flexible dienes at room temperature.
环 closing metathesis（RCM）为大环化合物提供了多种催化途径，应用范围从香水到生产抗病毒药物。然而，不需要的低聚化是一个长期存在的挑战。低聚物可以通过足够反应性的催化剂转化为环状目标物，促进 backbiting（例如，N-杂环卡宾的 Ru 配合物；NHCs），但催化剂分解限制了产率和选择性。将半配位邻二苯胺（ODA）螯合物引入新型 RuCl（NHC）（ODA）（=CHPh）催化剂中，可以加速大环化，特别是对于带有可以形成氢键的极性位点的二烯：它也可能抑制复分解过程中的催化剂分解。与之前的 Ru-NHC 催化剂相比，结果有了显著的提高，在室温下，构象灵活的二烯可以快速进行大环化。
