Zuo Honghua, Qu Zheng-Wang, Kemper Sebastian, Klare Hendrik F T, Grimme Stefan, Oestreich Martin
Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 115, 10623 Berlin, Germany.
Mulliken Center for Theoretical Chemistry, Clausius-Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstraße 4, 53115 Bonn, Germany.
J Am Chem Soc. 2024 Nov 20;146(46):31377-31383. doi: 10.1021/jacs.4c09885. Epub 2024 Nov 6.
A (3 + 2) annulation of allenyl- and, after rapid isomerization, propargylsilanes with internal 1-aryl-1-alkynes to form 4-methylenecyclopentenes is reported. The reaction is initiated by a silylium ion, and the catalytic cycle is subsequently maintained by the self-regeneration of the silylium-ion promoter. Unlike the well-established Danheiser annulation, where the allenylsilane serves as a , the present transformation engages the allenylsilane as a . Experimental observations and DFT calculations unveil a reaction cascade involving various β-silicon-stabilized carbocations, where a pentadienyl-to-allyl cation electrocyclization is the key step.
据报道，烯丙基硅烷以及在快速异构化后生成的炔丙基硅烷与内型1-芳基-1-炔烃发生(3 + 2)环化反应，生成4-亚甲基环戊烯。该反应由硅鎓离子引发，随后通过硅鎓离子促进剂的自再生维持催化循环。与成熟的丹海泽环化反应不同，在丹海泽环化反应中烯丙基硅烷用作[此处原文缺失内容]，而目前的转化反应中烯丙基硅烷用作[此处原文缺失内容]。实验观察和密度泛函理论计算揭示了一个涉及各种β-硅稳定碳正离子的反应级联，其中戊二烯基到烯丙基阳离子的电环化是关键步骤。
