Universität zu Köln

Taspinar, Oemer, Wilczek, Tobias, Erver, Julian, Breugst, Martin ORCID: 0000-0003-0950-8858, Neudoerfl, Joerg-Martin and Schmalz, Hans-Guenther ORCID: 0000-0003-0489-1827 (2020). Synthesis of the 8,19-Epoxysteroid Eurysterol A. Chem.-Eur. J., 26 (19). S. 4256 - 4261. WEINHEIM: WILEY-V C H VERLAG GMBH. ISSN 1521-3765

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Abstract

We report the first chemical synthesis of eurysterol A, a cytotoxic and antifungal marine steroidal sulfate with a unique C8-C19 oxy-bridged cholestane skeleton. After C19 hydroxylation of cholesteryl acetate, used as an inexpensive commercial starting material, the challenging oxidative functionalization of ring B was achieved by two different routes to set up a 5 alpha-hydroxy-7-en-6-one moiety. As a key step, an intramolecular oxa-Michael addition was exploited to close the oxy-bridge (8 beta,19-epoxy unit). DFT calculations show this reversible transformation being exergonic by about -30 kJ mol(-1). Along the optimized (scalable) synthetic sequence, the target natural product was obtained in only 11 steps in 5 % overall yield. In addition, an access to (isomeric) 7 beta,19-epoxy steroids with a previously unknown pentacyclic ring system was discovered.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Taspinar, Oemer UNSPECIFIED UNSPECIFIED UNSPECIFIED Wilczek, Tobias UNSPECIFIED UNSPECIFIED UNSPECIFIED Erver, Julian UNSPECIFIED UNSPECIFIED UNSPECIFIED Breugst, Martin UNSPECIFIED orcid.org/0000-0003-0950-8858 UNSPECIFIED Neudoerfl, Joerg-Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmalz, Hans-Guenther UNSPECIFIED orcid.org/0000-0003-0489-1827 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-339305
DOI:	10.1002/chem.202000585
Journal or Publication Title:	Chem.-Eur. J.
Volume:	26
Number:	19
Page Range:	S. 4256 - 4261
Date:	2020
Publisher:	WILEY-V C H VERLAG GMBH
Place of Publication:	WEINHEIM
ISSN:	1521-3765
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Organic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MARINE NATURAL-PRODUCTS; INTRAMOLECULAR HYDROGEN ABSTRACTION; DESS-MARTIN PERIODINANE; OXA-MICHAEL REACTION; CARBON DOUBLE-BONDS; CATALYZED DIHYDROXYLATION; STEREOSELECTIVE-SYNTHESIS; POLYOXYGENATED STEROIDS; SECONDARY ALCOHOLS; IODINE(V) REAGENTS Multiple languages Chemistry, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/33930