Volume 61, Issue 44 e202211596
Research Article

Enantioselective [2+2] Cycloaddition of Allenyl Imide with Mono- or Disubstituted Alkenes

Wanlong Xiao

Wanlong Xiao

Key laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064 China

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Lichao Ning

Lichao Ning

Key laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064 China

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Shuang Xin

Shuang Xin

Key laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064 China

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Prof. Dr. Shunxi Dong

Prof. Dr. Shunxi Dong

Key laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064 China

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Prof. Dr. Xiaohua Liu

Corresponding Author

Prof. Dr. Xiaohua Liu

Key laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064 China

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Prof. Dr. Xiaoming Feng

Corresponding Author

Prof. Dr. Xiaoming Feng

Key laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064 China

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First published: 13 September 2022
Citations: 29

Graphical Abstract

An efficient catalytic asymmetric [2+2] cycloaddition reaction of allenyl imide and alkenes was achieved by utilizing chiral N,N′-dioxide-magnesium(II) complex as the catalyst. This protocol provided a series of axially chiral cyclobutenes in high yields with excellent enantioselectivities. A stepwise mechanism was proposed based on experimental studies and DFT calculations and π–π stacking interaction was crucial for the enantioselectivity.

Abstract

An efficient catalytic asymmetric [2+2] cycloaddition of allenyl imide and mono- or disubstituted alkenes is disclosed. The key feature of this method is the use of bidentate allenyl imide and weakly activated and less steric hindered alkene pair by utilizing chiral magnesium(II) complex of N,N′-dioxide, which could provide through-space dispersion interactions to orientate the arrangement of the alkene. This protocol allows the generation of a series of axially chiral cyclobutenes and four-membered ring-containing spirocycles (80 examples) in high yield (up to 99 %) with excellent enantioselectivity (up to >99 % ee), and the late-stage modification of biologically active molecules as well. Experimental studies and DFT calculations revealed that this [2+2] cycloaddition proceeded via a stepwise mechanism involving a short-lived zwitterionic intermediate. The π-π interaction between the alkenes and the amide moiety in the ligand was crucial for the enantiocontrol.

Conflict of interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

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