Aspyrone (1) was elaborated in an optically pure form by a key reaction involving the highly diastereoselective addition of tetrahydropyranone enol ate to 2-tosyloxy-aldehyde and the subsequent in situ formation of an epoxide.
Isolation, Structure, and Total Synthesis of the Marine Macrolide Mangrolide D
作者:Junyu Gong、Wei Li、Peng Fu、John MacMillan、Jef K. De Brabander
DOI:10.1021/acs.orglett.9b01126
日期:2019.4.19
The isolation, characterization, and totalsynthesis of the macrocyclic polyene mangrolide D is reported. A 16-step totalsynthesis relies on robust Suzuki and ring-closing metathesis reactions, and an iron-catalyzed hydroazidation of an exomethylene substituted tetrahydropyran as a key step for the synthesis of the appended 4- epi-vancosamine sugar. Although mangrolide D did not display antibiotic
The macrocyclic antibiotic mangrolide A has been described to exhibit potent activity against a number of clinically important Gram‐negative pathogens. Reported is the first enantioselective totalsynthesis of mangrolide A and derivatives. Salient features of this synthesis include a highly convergent macrocycle preparation, stereoselective synthesis of the disaccharide moiety, and two β‐selective
Me<sub>3</sub>SI-promoted chemoselective deacetylation: a general and mild protocol
作者:Aakanksha Gurawa、Manoj Kumar、Sudhir Kashyap
DOI:10.1039/d1ra03209g
日期:——
Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developed via employing KMnO4 as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses
Untersuchungen zur Darstellung von Desoxyzucker-Steroidglycosiden
作者:Joachim Thiem、Sabine Köpper、Jens Schwentner
DOI:10.1002/jlac.198519851105
日期:1985.11.12
Glycosylierung von Triacetyldigitoxose 21 mit Digitoxigenin führt bei Ausbeuten von maximal 50% zu den α- und β-Anomeren 10 und 25 im Verhältnis ca. 2:3. Höhere Temperaturen steigern den relativen Anteil an β-Komponente bei stark fallenden Ausbeuten. Die Glycosylierung von Acetobromdigitoxose 22 mit unterschiedlichen Silbersalzen ergibt ebenfalls bei Ausbeuten von ca. 50% Anomerenverhältnis von α:β = 2:3