Efficient [3 + 2] annulations of N-aryl-C,C-diphenyl ketenimines with metallo-carbonyl and metallo-azomethine ylides, generated via the respective Yb(OTf)₃ and Y(OTf)₃ promoted carbon–carbon bond heterolysis of donor–acceptor oxiranes and aziridines, have been accomplished. These reactions proceeded under mild conditions and supplied a general methodology for the regioselective construction of structurally complex oxazolidines and pyrrolidines. Moreover, heating neat mixtures of N-aryl-C,C-diphenyl ketenimines and diethyl aziridine-2,3-dicarboxylates led to imidazolidine derivatives. A computational study concluded in stepwise mechanisms for these [3 + 2] annulations, also shedding light on their regioselectivity, concerning which of the two cumulated double bonds of the ketenimine becomes involved in the reaction with the ylide.

中文翻译：

---

酮亚胺的区域选择性[3 + 2]环与供体-受体环氧乙烷和氮丙啶的位置接近，获得多取代的恶唑烷，吡咯烷和咪唑烷†

分别通过Yb（OTf）₃和Y（OTf）₃生成的N-芳基C，C-二苯基酮亚胺与金属羰基和金属偶氮甲亚胺的高效[3 + 2]环化促进了碳的碳-碳键杂合供体-受体环氧乙烷和氮丙啶已完成。这些反应在温和的条件下进行，并为结构复杂的恶唑烷和吡咯烷的区域选择性构建提供了一般方法。而且，加热N-芳基-C，C的纯净混合物-二苯基酮亚胺和二乙基氮丙啶-2，3-二羧酸酯生成咪唑烷衍生物。对这些[3 + 2]环的逐步机理的计算研究得出了结论，并且也揭示了它们的区域选择性，涉及酮亚胺的两个累积双键中的哪一个参与了与叶立德的反应。