A variety of N-vinylindoles and N-vinylpyrroles were prepared in moderate to good yields through the nickel(II)-catalyzed [3 + 2] cycloaddition of α,β-unsaturated nitrones with allenoates under mild reaction conditions. A rational mechanism for the formation of N-vinylindoles was proposed based on the ¹⁸O-labeled experiments and key intermediates detected by high-resolution mass spectrometry trace experiments. The present method highlights a nickel(II)-controlled cyclization, atom-economical reaction, broad substrate scope, good functional group tolerance, and high Z-stereoselectivity for the enamine bond.

中文翻译：

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镍 (II) 催化 [3 + 2] 环加成硝酮和烯丙酸酯以获取 N-乙烯基吲哚和 N-乙烯基吡咯

在温和的反应条件下，通过镍 (II) 催化的 α,β-不饱和硝酮与烯丙酸酯的 [3 + 2] 环加成反应，以中等至良好的收率制备了多种N-乙烯基吲哚和N-乙烯基吡咯。基于^18个O标记实验和高分辨率质谱痕量实验检测到的关键中间体，提出了N-乙烯基吲哚形成的合理机制。本方法突出了镍 (II) 控制的环化、原子经济反应、广泛的底物范围、良好的官能团耐受性和烯胺键的高 Z 立体选择性。