A Diels-Alder reaction / oxa-Michael addition / acyloin rearrangement cascade on tropolonic substrates. Issue 16 (18th April 2018)

• Record Type: Journal Article
• Authors: Eugui, Macarena; Rasquin, Katerine; Radcenco, Andrés López; Suescun, Leopoldo; Moyna, Guillermo
• Is Part Of: Tetrahedron letters. Volume 59:Issue 16(2018)
• Page Start: 1560
• Page End: 1563
• Publication Date: 2018-04-18
• Subjects: Acyloin rearrangement -- Cascade reaction -- Deuterium labelling -- Diels-Alder cycloaddition -- Oxa-Michael addition; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2018.03.022
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: A novel pericyclic/anionic cascade reaction on tropolonic subtrates is described. It involves a Diels-Alder reaction and an oxa-Michael addition catalytic cycle. Stabilization of reaction intermediates by intramolecular H-bonding is required. Structurally complex natural product-like compounds are obtained in a single step. Abstract: We describe a novel pericyclic/anionic cascade reaction on tropolonic substrates that combines a Diels-Alder reaction, an oxa-Michael addition, and an acyloin rearrangement to afford tricyclic α-hydroxy-β-methoxyketones. Spectroscopic, crystallographic, and mechanistic studies indicate that the process requires stabilization of reaction intermediates through intramolecular H-bonding to take place, and suggest that the conjugate addition step involves a catalytic cycle with initial formation of an ammonium enolate and sustained by an alkoxide ion pair. Given the rich functionality and structural complexity generated in a single step, the process could be exploited in the preparation of natural product-like compound libraries.