Bifunctional Iron Catalyst for Endoselective Cycloisomerization of Nucleophile-Functionalized Terminal Alkynes

The catalytic cycloisomerization of nucleophile-functionalized alkynes is a useful method for the synthesis of heterocyclic compounds with 100% atom economy. Group 8 catalysts give high endoselectivity in these transformations due to their ability to invoke metal-vinylidene intermediates. While many ruthenium and osmium catalysts have been reported, the iron counterpart is underdeveloped. Herein we report a well-defined molecular iron catalyst that can convert a variety of nucleophile-functionalized alkynes into the corresponding heterocycles in an endo-selective manner at ambient temperature and the mechanistic insight of the endoselectivity.

亲核官能化炔烃的催化环异构化反应是一种具备100%原子经济性的杂环化合物合成方法。第8族催化剂因可介导金属-亚乙烯基中间体的生成，在该类转化中展现出优异的内选择性。尽管已有诸多钌、锇基催化剂被报道，但对应的铁基催化剂的开发仍相对不足。本文报道了一种结构明确的分子铁催化剂，其可在室温条件下以高内选择性将各类亲核官能化炔烃转化为相应杂环化合物，并阐明了该内选择性的反应机理。