Ruthenium-Catalyzed Transfer Oxygenative Cyclization of α,ω-Diynes: Unprecedented [2 + 2 + 1] Route to Bicyclic Furans via Ruthenacyclopentatriene

A novel oxygen-atom-transfer process enables the catalytic [2 + 2 + 1] synthesis of bicyclic furans from α,ω-diynes with DMSO. [CpRu­(AN)3]­PF6 catalyzed the transfer oxygenative cyclization of diynes with aryl terminal groups, while those of diynes with alkyl terminal groups were effectively promoted by the corresponding Cp* complex. A mechanism for bicyclic furan formation via a ruthenacyclopentatriene was proposed on the basis of both experimental and theoretical studies.

一种新型氧原子转移反应可实现以二甲基亚砜（DMSO）为氧供体，由α,ω-二炔经催化[2+2+1]环化合成双环呋喃的反应。六氟磷酸三(乙腈)环戊二烯合钌([CpRu(AN)₃]PF₆)可催化带有芳基端基的二炔的氧转移环化反应，而带有烷基端基的二炔的该类反应则可由对应的五甲基环戊二烯基（Cp*）配合物有效促进。基于实验与理论研究，研究者提出了一条经由钌杂环戊三烯中间体生成双环呋喃的反应机理。