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Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
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Tandem [3 + 2] Cycloaddition Reaction: Access to Polycyclic Quinolinone-Fused Pyrrolo[2,1-a]isoquinoline Scaffolds

Chi Zhang1, Chuanhu Gao1, Yulu Shuai1

  • 1School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou, Henan450001, P. R. China.

The Journal of Organic Chemistry
|August 14, 2026
PubMed

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Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
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