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Unlike secondary alkyl amines and electron-rich anilines, secondary electron-poor anilines are challenging amine sources to explore the chemical space of Lewis acid-catalyzed condensation-based transformations with furfural. In this work, we report the efficient synthesis of trans -4,5-diamino cyclopentenones (DCP) using a high-pressure promoted Nazarov-like electrocyclization of Stenhouse salts arising from the Sc(III)-catalyzed condensation of furfural with secondary electron-poor anilines. The reaction enables access to otherwise difficult-to-access DCP and compatibility with a large scope of alkyl and aryl secondary amines. A 2- to 18-fold increase in yields for electron-poor anilines was highlighted using this approach in the synthesis of a pharmacologically active compound.

Natural products containing aminocyclopentanes are common secondary metabolites, often biologically active. This work aims at the preparation of a useful synthon for total synthesis containing orthogonally protected amines. To this end, furfural and two amines were employed to form mixed trans -4,5-diaminocyclopentenones promoted by Cu(OTf) 2 . The selected amines can be orthogonally deprotected, allowing selective modification of the amines on the cyclopentane core. Their utility was showcased for the total synthesis of highly complex (±)-Agelastatin A.

trans-4,5-Diamino-cyclopent-2-enones (CP) are usually prepared by Lewis acid-catalyzed condensation of furfural and a secondary amine in an organic solvent. The reaction proceeds through the formation of a Stenhouse salt (SS) intermediate followed by an electrocyclization reaction to afford the desired CP. Herein, we described the use of Cu(OTf) 2 as a very efficient catalyst for the synthesis of CP in water at room temperature. Furthermore, the mild reaction conditions, catalyst reusability, and outstanding functional group tolerance suggest that this CP platform can be further used in chemical biology.