Li MJ, Xiao HJ, Xu P, Wu LT, Chen SQ, Zhang Z, Xu H. Mechanosynthesis of Pyrrole-2-carboxylic Acids via Copper-Catalyzed Spiroannulation/Ring-Opening Aromatization of 4-Arylidene Isoxazol-5-ones with Enamino Esters.
Org Lett 2024;
26:4189-4193. [PMID:
38743432 DOI:
10.1021/acs.orglett.4c00829]
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Abstract
An efficient and practical tandem reaction of 4-arylidene isoxazol-5-ones with enamino esters catalyzed by an inexpensive copper salt has been established in a ball mill. This innovative approach yields a diverse array of structurally novel pyrrole-2-carboxylic acids, showing excellent tolerance toward different functional groups. By integrating spiroannulation and ring-opening aromatization processes, this protocol introduces a facile and cost-effective strategy for synthesizing highly functionalized pyrrole derivatives.
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