Zhang Rui, Xia Ying, Dong Guangbin
Department of Chemistry, The University of Chicago, 5735 S Ellis Ave, Chicago, IL, 60637, USA.
Angew Chem Int Ed Engl. 2021 Sep 6;60(37):20476-20482. doi: 10.1002/anie.202106007. Epub 2021 Aug 3.
Herein, we report a [5+2] cycloaddition between readily accessible 1-indanones and internal alkynes through Rh-catalyzed activation of less strained C-C bonds. The reaction is enabled by a strongly σ-donating NHC ligand and a carefully modified temporary directing group. A wide range of functional groups is tolerated, and the method provides straightforward access to diverse benzocycloheptenones that are hard to access otherwise. DFT studies of the reaction mechanism imply the migration insertion as the turnover-limiting step and suggest beneficial π-π interactions in the transition states.
在此，我们报道了通过铑催化活化张力较小的碳-碳键，使易于获得的1-茚酮与内炔烃之间发生[5+2]环加成反应。该反应由强σ供体NHC配体和精心修饰的临时导向基团实现。该方法能耐受多种官能团，且能直接合成其他方法难以获得的多种苯并环庚烯酮。反应机理的密度泛函理论研究表明迁移插入是周转限制步骤，并表明过渡态中存在有益的π-π相互作用。
