北京大学余志祥团队开发了环丁烷C-C裂解的双活化策略：铑、锌共催化乙烯基环丁酮[4 + 2]环加成反应的进展及机理。相关研究成果发表在2022年11月16日出版的《美国化学会杂志》。

该文报道了新设计的炔-乙烯基环丁烷酮的Rh和Zn共催化[4+2]环加成反应，该反应可以产生具有全碳四元桥头堡中心5/6或6/6的双环产物。该反应具有广泛的范围，可以实现从富含对映体的底物到环加合物的手性转移。该[4+2]反应成功的关键是向环丁烷酮中引入乙烯基，这有助于通过氧化加成将乙烯基环丁烷酮C–C裂解。该C–C裂解步骤通过锌与乙烯基环丁酮羰基的配位协同辅助。

同样重要的是，进行了可视化动力学分析和计算研究，以支持速率决定C–C裂解中的双重活化，推导[4+2]反应的速率规律，了解Zn在帮助阳离子Rh催化剂原位生成和防止催化剂失活方面的另一作用，并分析所涉及的关键过渡态和中间体。

附：英文原文

Title: Dual Activation Strategy to Achieve C–C Cleavage of Cyclobutanes: Development and Mechanism of Rh and Zn Cocatalyzed [4 + 2] Cycloaddition of Yne-Vinylcyclobutanones

Author: Guan-Yu Zhang, Pan Zhang, Bing-Wen Li, Kang Liu, Jun Li, Zhi-Xiang Yu

Issue&Volume: November 16, 2022

Abstract: Reported here is the Rh and Zn cocatalyzed [4 + 2] cycloaddition of newly designed yne-vinylcyclobutanones, which can generate 5/6 or 6/6 bicyclic products with an all-carbon quaternary bridgehead center. The reaction has a broad scope and can realize chirality transfer from enantioenriched substrates to the cycloadducts. The key to the success of this [4 + 2] reaction is the introduction of a vinyl group to cyclobutanones, which helps the C–C cleavage of vinylcyclobutanones via oxidative addition. This C–C cleavage step is synergistically aided by Zn coordination to the carbonyl group of vinylcyclobutanones. Of the same importance, visual kinetic analysis and computational studies have been carried out to support the dual activation in the rate-determining C–C cleavage, to derive the rate law of the [4 + 2] reaction, to understand another role of Zn in helping the in situ generation of the cationic Rh catalyst and preventing catalyst deactivation, and to analyze the key transition states and intermediates involved.

DOI: 10.1021/jacs.2c04244

Source: https://pubs.acs.org/doi/10.1021/jacs.2c04244