Domino Aza‐Claisen/Mannich Cyclization Reaction from a Chiral α‐Alkoxy Enamine or Sequential Alkylation of an α‐Alkoxy Ester Enolate or Nitrile Anion, Followed by an Intramolecular Wittig Reaction: Two (3+2) Annulation Routes to Homochiral 4‐Alkyl‐4‐hydroxy‐2‐cyclopentenone Synthesis

Kuhn, Cyrille; Skaltsounis, Léandros; Monneret, Claude; Florent, Jean‐Claude

doi:10.1002/ejoc.200300045

Cited by 16 publications

(4 citation statements)

References 78 publications

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“…In synthetic efforts toward analogues of naturally occurring prostaglandins, Florent and co-workers developed a related ionic aza-Claisen/Mannich trio (Scheme 61). [93] Treatment of either diastereomer of aldehyde 277 with pyrrolidine resulted in a crude mixture of enamine isomers 278. Alkylation with an allylic iodide generated the ammonium 279, which underwent facile [3,3] rearrangement to iminium 280.…”

Section: Reaction Cascadesmentioning

confidence: 99%

Toward a Symphony of Reactivity: Cascades Involving Catalysis and Sigmatropic Rearrangements

et al. 2014

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Catalysis and synthesis are intimately linked in modern organic chemistry. The synthesis of complex molecules is an ever evolving area of science. In many regards, the inherent beauty associated with a synthetic sequence can be linked to a certain combination of the creativity with which a sequence is designed and the overall efficiency with which the ultimate process is performed. In synthesis, as in other endeavors, beauty is very much in the eyes of the beholder.[**] It is with this in mind that we will attempt to review an area of synthesis that has fascinated us and that we find extraordinarily beautiful, namely the combination of catalysis and sigmatropic rearrangements in consecutive and cascade sequences.

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Section: Reaction Cascadesmentioning

confidence: 99%

Toward a Symphony of Reactivity: Cascades Involving Catalysis and Sigmatropic Rearrangements

et al. 2014

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“…Florent and co-workers also reported the enantioselective synthesis of 4-alkyl-4-hydroxycyclopentenone 1334 via tandem cationic aza-Claisen rearrangement and Mannich cyclization (Scheme ). This crucial intermediate was used for the synthesis of clavulone II described above …”

Section: Cyclopentenone Prostanoids: Prostaglandins Clavulones and Ph...mentioning

confidence: 99%

Synthesis of Chiral Cyclopentenones

et al. 2016

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The cyclopentenone unit is a very powerful synthon for the synthesis of a variety of bioactive target molecules. This is due to the broad diversity of chemical modifications available for the enone structural motif. In particular, chiral cyclopentenones are important precursors in the asymmetric synthesis of target chiral molecules. This Review provides an overview of reported methods for enantioselective and asymmetric syntheses of cyclopentenones, including chemical and enzymatic resolution, asymmetric synthesis via Pauson-Khand reaction, Nazarov cyclization and organocatalyzed reactions, asymmetric functionalization of the existing cyclopentenone unit, and functionalization of chiral building blocks.

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“…Starting from easily accessible aldehyde 521 , this sequence afforded the cyclopentenones 522 in a one-pot reaction and in 40% yield. From this compound, a sequence of six classical steps yielded the chiral 4-hydroxycyclopentenone 526 , which was already known as a key intermediate for clavulone II synthesis (Scheme ) 104 …”

Section: 4 Clavulones and Analoguesmentioning

confidence: 99%