Novel π2s+π2a Electrocyclization of Triethylenic‐Malonic Acids Exemplified for a One‐Pot Synthesis of New γ‐Dilactones cis‐Fused with a Cyclopentene. (27th May 2015)

• Record Type: Journal Article
• Authors: Dillenschneider, Jean‐Marc; Dufossé, Laurent; Fouillaud, Mireille; Sutthiwong, Nuthathai; Labia, Roger; Valla, Alain
• Is Part Of: Journal of heterocyclic chemistry. Volume 53:Number 4(2016:Jul.)
• Page Start: 1017
• Page End: 1021
• Publication Date: 2015-05-27
• Subjects: Heterocyclic compounds -- Periodicals; 547.59
• DOI: 10.1002/jhet.2419
• Languages: English
• ISSNs: 0022-152X

Abstract

Abstract : A new, easy and rapid synthesis of γ‐dilactones is cis ‐fused with a cyclopentenic ring viacyclization of 7‐chlorotriethylenic‐malonic acids. The key step implicates anintramolecular cyclization to a cyclopentenyl cation, according to an electrocyclic π2s + π2a conrotatory process. This cyclopentenyl cation led to unstable γ‐lactones intermediates that are rearrange to more stable isomers. δ‐lactones (6 Z and 6 E ‐(3‐chlorobut‐2‐en‐2‐yl)‐5‐methyl‐3, 6‐dihydro‐2 H ‐pyran‐2‐one) were obtained as secondary products. Mechanistic pathways were considered. The structures of the newly synthesized compounds were established by elemental and spectral data. Abstract :