Regio‐ and Diastereoselective Formal [2+2] Cycloaddition of Allenes with Amino‐Functionalized Alkenes by Rare‐Earth‐Catalyzed C(sp2)-H Activation
Regio‐ and Diastereoselective Formal [2+2] Cycloaddition of Allenes with Amino‐Functionalized Alkenes by Rare‐Earth‐Catalyzed C(sp2)-H Activation
复制标题
通过稀土催化的 C(sp2)-H 活化，艾伦烯与氨基官能化烯烃的区域和非对映形式 [2+2] 环加成反应
DOI：
10.1002/anie.202210624
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Hou Zhaomin
中科院分区：
文献类型：
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作者：
Xu Wenxuan;Cong Xuefeng;An Kun;Lou Shao‐Jie;Li Zhenghua;Nishiura Masayoshi;Murahashi Tetsuro;Hou Zhaomin
联烯与烯烃的[2+2]环加成作为构建四元碳环的直接途径非常有趣和重要，但迄今为止仍然探索不足。本文首次报道了在半夹心稀土催化剂作用下，一系列联烯与氨基官能化烯烃的分子间区域选择性和非对映选择性的[2+2]环加成反应。该反应通过丙二烯C（sp2）−H活化机制进行，该机制由稀土金属烷基物种对丙二烯单元的位点选择性去质子化引发，随后烯烃插入到所得的金属丙二烯键中，随后分子内环加成到丙二烯C=C键。该方案提供了一个独特的路线，用于合成一个新的家庭的环丁烷和环丁烯衍生物，这是以前难以访问。
The [2+2] cycloaddition of allenes with alkenes is of much interest and importance as a straightforward route for the construction of four‐membered carbocycles but has remained much underexplored to date. Herein we report for the first time the intermolecular regio‐ and diastereoselective formal [2+2] cycloaddition of a wide range of allenes with amino‐functionalized alkenes by half‐sandwich rare‐earth catalysts. The reaction proceeded through an allene C(sp2)−H activation mechanism initiated by the site‐selective deprotonation of the allene unit by a rare‐earth metal alkyl species followed by alkene insertion into the resulting metal‐allenyl bond and the subsequent intramolecular cycloaddition to an allene C=C bond. This protocol offers a unique route for the synthesis of a new family of cyclobutane and cyclobutene derivatives which were difficult to access previously.