Long Yongjie, Shen Jiahao, Shi Min, Wei Yin
State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
Molecules. 2024 Dec 30;30(1):103. doi: 10.3390/molecules30010103.
Zwitterionic π-allenyl palladium species are newly developed intermediates. A substrate-controlled step existed in the cycloaddition of zwitterionic π-allenyl palladium species with tropsulfimides or tropones. With the assistance of previously experimental studies, zwitterionic allenyl/propargyl palladium species was provenly found by HRMS. Further DFT calculation studies show that zwitterionic π-allenyl palladium species are generated through the oxidative addition of Pd(0), which can be promoted by Lewis acid like Yb(OTf), and the cycloaddition more likely undergoes through an outer sphere nucleophilic attack. The isomerization is caused by the difference of dissociation energy between the cycloaddition intermediation of tropsulfimides and tropones, forming the substrate-controlled specificity.
两性离子π-烯丙基钯物种是新开发的中间体。两性离子π-烯丙基钯物种与托普磺酰亚胺或环庚三烯酮的环加成反应中存在底物控制步骤。在先前实验研究的帮助下，通过高分辨质谱法证实发现了两性离子烯丙基/炔丙基钯物种。进一步的密度泛函理论计算研究表明，两性离子π-烯丙基钯物种是通过Pd(0)的氧化加成产生的，这可以由Yb(OTf)等路易斯酸促进，并且环加成更可能通过外层亲核进攻进行。异构化是由托普磺酰亚胺和环庚三烯酮环加成中间体之间解离能的差异引起的，形成了底物控制的特异性。
