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Updated: Jun 10, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Formal (4 + 1)-Cycloadditions of Donor-Acceptor Cyclobutanes and Isocyanides: Access to β-Enamino-diesters and
Enzo Charbonneau1, Jean-François Fournier1, David Tong1
1Department of Chemical Sciences, Paraza Pharma Inc., 2525 Marie-Curie Avenue, Montréal, Québec H4S 2E1, Canada.
Abstract:
In this work, a synthetic protocol for accessing substituted five-membered carbocyclic β-enamino-diesters from isocyanides and donor-acceptor (D-A) cyclobutanes is described. A formal (4 + 1)-cycloaddition furnishes β-enamino-diesters in up to 89% yield from various aliphatic and aromatic isocyanides. In addition, a tandem formal (4 + 1)-cycloaddition followed by decarboxylative tautomerization is demonstrated in a preliminary example, enabling the selective formation of a β-enaminoester.
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