Synthesis of 1,3-dioxin-4-ones and their use in synthesis. Part XXII. A novel synthetic method for tetronic acids from 1,3-dioxin-4-ones via intra- or intermolecular ketene trapping.
Novel synthetic routes to tetronic acid and its derivatives from 6-substituted 1, 3-dioxin-4-ones through cycloreversion to acylketenes followed by either intra- or intermolecular ketene trapping by a hydroxy function is described. While tetronic acid and its 5-substituted derivatives were synthesized directly from 6-(x-hydroxyalky)-1, 3-dioxin-4-ones by intramolecular trapping, 3-acyltetronic acids were prepared by Dieckmann reaction of the β-keto esters obtained from the 6-substituted dioxinones and an approptiate α-hydroxy ester by intermolecdular trapping.
Microbial metabolites. Part XI. Total synthesis and absolute configuration of (S)-carlosic acid (4-butyryl-2,5-dihydro-3-hydroxy-5-oxo-furan-2-acetic acid) and conversion of (R)-5-methyltetronic acid into (R)-carolic acid {3,4-dihydro-8-methylfuro[3,4-b]oxepin-5,6(2H,8H)-di-one}
作者:James L. Bloomer、Francis E. Kappler
DOI:10.1039/p19760001485
日期:——
of (S)-2,5-dihydro-3-hydroxy-5-oxofuran-2-acetic acid (5) and its methyl ester are described. Biomimetic acylations of the ester and of (R)-3-hydroxy-2-methylfuran-2(5H)-one[(R)-γ-methyltetronic acid](1) to produce (S)-carlosicacid (3) and (R)-carolicacid (2), respectively, are described. The absoluteconfiguration of carlosic acid from Penicillium charlesii NRRL 1887 has been established as S.