56427-31-7Relevant academic research and scientific papers
Total synthesis of (S)-(+)-ent-phomapyrones B and surugapyrone B
Ohmukai, Hiroaki,Sugiyama, Yasumasa,Hirota, Akira,Kirihata, Mitsunori,Tanimori, Shinji
, p. 1090 - 1100 (2019/12/24)
Phomapyrone B (1), the 2-pyrones isolated from the phytopathogenic fungus Leptosphaeria maculans, has been synthesized as the enantiomeric form starting from (S)-2-methylbutanol (4). Surugapyrone B (3) isolated from Streptmyces sp. USF-6280 as an antioxidant has also been synthesized as a natural form. The absolute configuration of phomapyrone B (1) was estimated to be the (R)-form and that of surugapyrone B (3) being the (S)-form. A series of 2-pyrone derivatives 17 have been synthesized through the established procedure and their DPPH radical-scavenging activities have also been evaluated.
Access to Tetronic Acids via Silver-Catalyzed CO2 Incorporation into Conjugated Ynones
Sadamitsu, Yuta,Komatsuki, Keiichi,Saito, Kodai,Yamada, Tohru
supporting information, p. 3191 - 3194 (2017/06/23)
Facile and versatile access to highly functionalized tetronic acids has been successfully achieved through the reaction of conjugated ynones with carbon dioxide. In the presence of a base, the enolates generated from the ynones capture CO2 via
Gold- or Silver-Catalyzed Syntheses of Pyrones and Pyridine Derivatives: Mechanistic and Synthetic Aspects
Preindl, Johannes,Jouvin, Kvin,Laurich, Daniel,Seidel, Günter,Fürstner, Alois
supporting information, p. 237 - 247 (2016/01/25)
3-Oxo-5-alkynoic acid esters, on treatment with a carbophilic catalyst, undergo 6-endo-dig cyclization reactions to furnish either 2-pyrones or 4-pyrones in high yields. The regiochemical course can be dialed in by the proper choice of the alcohol part of the ester and the π-acid. This transformation is compatible with a variety of acid-sensitive groups as witnessed by a number of exigent applications to the total synthesis of natural products, including pseudopyronine A, hispidine, phellinin A, the radininol family, neurymenolide, violapyrone, wailupemycin and an unnamed brominated 4-pyrone of marine origin. Although the reaction proceeds well in neutral medium, the rate is largely increased when HOAc is used as solvent or co-solvent, which is thought to favor the protodeauration of the reactive alkenyl-gold intermediates as the likely rate-determining step of the catalytic cycle. Such intermediates are prone to undergo diauration as an off-cycle event that sequesters the catalyst; this notion is consistent with literature data and supported by the isolation of the gem-diaurated complexes 12 and 15. Furthermore, silver catalysis allowed access to be gained to 2-alkoxypyridine and 2-alkoxyisoquinoline derivatives starting from readily available imidate precursors.
