The winner takes it al‐dol: The total synthesis of auripyrones A and B was achieved using a diastereoselective aldol‐type reaction with 2,6‐diethyl‐3,5‐dimethyl‐4‐pyrone as a key step. The stereostructure and absoluteconfiguration of auripyrone B has also been determined.
Stereoselektive Synthese von Alkoholen, IX. Absolute Konfiguration von Stegobinon
作者:Reinhard W. Hoffmann、Wolfgang Ladner、Klaus Steinbach、Werner Massa、Roland Schmidt、Günther Snatzke
DOI:10.1002/cber.19811140811
日期:1981.8
Eine diastereo- und enantioselektive Synthese des Homoallylalkohols 5 aus dem Boronester 4 eröffnete den Zugang zu optisch aktiven Isomeren des Stegobinons. Stegobinon-Isomere mit der richtigen absoluten Konfiguration an C-2 wurden ausgehend von (3S)-3-Hydroxy-2-methylbuttersäureester 17 dargestellt. Das CD-Spektrum des Isomeren 20B entsprach dem des Naturstoffs. Daraus wurde die konfiguration zu 2S
Eine非对映体和对映体合成人5硼烷合成体4链刚体优化体Stegobinons。Stegobinon-Isomere mit der der richtigen Konfiguration一架C-2炸药(3S)-3-羟基-2-甲基丁二酸酯17 dargestellt。Naturstoffs的CD CD-Spektrum des Isomeren 20B。Daraus wurde模具konfigurationつ2S,3R,7R献给DASnatürlicheStegobinon abgeleitet UND第三人以EINERöntgenstrukturanalyseDES 7- Epistegobinons(20A)erhärtet。
Toward the synthesis of γ-pyrone-containing natural products: diastereoselective aldol-type reaction of a γ-pyrone
The diastereoselective aldol-type reaction of a γ-pyrone via a sodium anion has been developed. This reaction is useful for synthesizing γ-pyrone-containing natural products. Also, we applied the Mukaiyama aldol-type reaction of silyl enol ether of γ-pyrone by using TiCl4. This Mukaiyama aldol-type reaction of γ-pyrone indicated higher anti-aldol selectivity than the aldol-type reaction of a γ-pyrone
A straightforward approach to 4-pyrone-containing natural products has been developed, which includes an aldol-type reaction between 2,6-diethyl-3,5-dimethyl-4-pyrone and aldehydes. The counter cation of the carbanion of the pyrone was found to play an important role in this reaction.
Intramolecular carboxylic acid trapping of pyran-4-one derived zwitterions: A novel synthesis of fused bicyclic lactones
作者:F.G. West、C.M. Amann、P.V. Fisher
DOI:10.1016/0040-4039(94)88351-3
日期:1994.12
Pyran-4-ones bearing carboxylic acid side chains were prepared either by direct carboxylation with carbon dioxide or through oxidative cleavage of side chain olefins. Irradiation in a non-nucleophilic solvent yielded fused bicyclic lactones. The efficiency of the reaction was not dependent on ring substitution.