The Total Synthesis of Estrone and Three Stereoisomers Including Lumiestrone

Abstract

The total synthesis of four of the eight possible racemates having the estrone structure has been described. One of these proved to be the dl-iotm of the natural hormone, and has been resolved. Another has been identified as lumiestrone. The synthetic scheme employed is summarized below. The potassium salt of m-methoxyphenylacetylene (prepared from m-hydroxyacetophenone) was added to decalin-l,5-dione in a 1:1 molecular ratio. The acetylenic bond of the resulting 28.34

Catalytic, Enantioselective, Intramolecular Carbosulfenylation of Olefins. Preparative and Stereochemical Aspects

“…In previous studies, cationic ring closures with m -anisole occurred at both C(2) and C(4) positions. 53 The enantiomeric ratio obtained for 29 was identical to that obtained for trans - 14n . For the phenyl substituted alkene ( E )- 11b , the cyclization led to the formation of constitutional isomers 31 and 32 in a 1:1 ratio.…”

Photochemische Reaktionen als Schlüsselschritte in der Naturstoffsynthese

“…[227] Zu den Klassikern der in diesem Aufsatz behandelten Totalsynthesen gehört die Synthese von (+)-Östron (156) durch Quinkert et al, in der eine intramolekulare DielsAlder-Reaktion eines photochemisch generierten orthoChinodimethans als Schlüsselschritt diente (Schema 43). [228] Nach Dehydratisierung und bereits literaturbekannten Transformationen [229] [231] auch wenn von den Autoren ein anderer Mechanismus vorgeschlagen wird. [232] Ein weiteres Beispiel ist die formale Totalsynthese von (AE )-Podophyllotoxin durch Kraus et al [233] Das bei der Bestrahlung von ortho-alkylierten aromatischen Aldehyden intermediär gebildete ortho-Chinodimethan kann auch in einer Hetero-Diels-Alder-Reaktion mit einem Aldehyd abgefangen werden.…”

Designing Total Syntheses

“…The degree of stereospecificity (absent in the methylation of 62) varies from compound to compound, and depends primarily on the stereochemistry of the material being methylated. Some of these influences are seen in the results of methylation of the isomeric 17a-ketones 69-72 (Scheme 1-7) [71][72][73]. These compounds were first condensed with aromatic aldehyde in order to protect the more reactive 17-position.…”