Synlett 2021; 32(12): 1201-1206
DOI: 10.1055/a-1506-4509
letter

Diastereoselective Synthesis of Spiropyrazolones via 1,3-Dipolar [3+2] Cycloadditions between Pyrazolone-Based Olefins and N,N′-Cyclic Azomethine Imines

Zhe Tang
,
Hui-Hui Wu
,
Xiao-Zu Fan
,
Heng Zhang
,
Lu-Yu Cai
,
Xiao-Fan Bi
,
Hong-Wu Zhao

We thank the Beijing Municipal Commission of Education (JC015001200902), the Beijing Municipal Natural Science Foundation (7102010, 2122008, and 2172003), the Basic Research Foundation of Beijing University of Technology (X4015001201101), the Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality (PHR201008025), the Doctoral Scientific Research Start-up Foundation of Beijing University of Technology (52015001200701) for financial supports.


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Abstract

Under the catalysis of PhCO2H, the 1,3-dipolar [3+2] cyclo­addition between pyrazolone-based olefins and N,N′-cyclic azomethine imines proceeded readily, thus delivering structurally novel spiropyrazolones with up to 98% yield and >20:1 dr. The relative stereochemical configuration of the obtained spiropyrazolones was unambiguously ­assigned by X-ray single-crystal structure analysis. The diastereoselective formation of the title spiropyrazolones was interpreted by the hypothesized reaction mechanism.

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Publication History

Received: 16 April 2021

Accepted after revision: 11 May 2021

Accepted Manuscript online:
11 May 2021

Article published online:
15 June 2021

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