广西师范大学莫冬亮团队报道了，Yb(OTf)₃催化n -乙烯基硝基酮与活化环丙烷的不对称[3+3]环加成制1,2-恶嗪。相关研究成果于2024年11月25日发表于国际顶尖学术期刊《中国化学》。

研究人员描述了Yb(OTf)₃与Pybox配体结合催化N-乙烯基肉桂醛硝酮，与活化环丙烷的不对称[3+3]环加成反应，以24%-95%的收率和22%-96%的ee制备各种官能化的1,2-恶嗪。实验结果表明，该反应分三步进行多米诺[3+3]加成、脱烯基化和氮杂-1,4-加成。

手性1,2-恶嗪可以以克为单位获得，很容易转化为各种1,2-恶嗪支架。该方法具有底物范围广、官能团相容性好、三组分多米诺反应，和N-乙烯基硝酮与活化环丙烷的不对称[3+3]环加成反应等特点。

附：英文原文

Title: Yb(OTf)3-Catalyzed Asymmetric [3+3] Cycloaddition of N-Vinyl Nitrones with Activated Cyclopropanes to Prepare 1,2-Oxazines

Author: Yu-Zheng Wu, Yue Leng, Yi-Xin Chen, Shi-Qiu Huang, Ning Zou, Chun-Hua Chen, Dong-Liang Mo

Issue&Volume: 2024-11-25

Abstract: We described a Yb(OTf)3 combined with Pybox ligand catalyzed asymmetric [3+3] cycloaddition of N-vinyl cinnamaldehyde nitrones with activated cyclopropanes to prepare various functionalized 1,2-oxazines in 24%—95% yields and 22%—96% ee. Experimental results revealed that the reaction underwent a domino [3+3] cycloaddition, dealkenylation, and aza-1,4-addition in three steps. The chiral 1,2-oxazine could be obtained in gram scales and easily converted into various 1,2-oxazine scaffolds. The present method features broad substrate scope, good functional group compatibility, three-component domino reaction, and asymmetric [3+3] cycloaddition of N-vinyl nitrones with activated cyclopropanes.

DOI: 10.1002/cjoc.202400937

Source: https://onlinelibrary.wiley.com/doi/full/10.1002/cjoc.202400937