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5,10:8,9-Disecosteroids (= Steroklastanes): A new type of modified steroids

✍ Scribed by Ljubrinka Lorenc; Lidija Bondarenko; Vlada Pavlović; Hermann Fuhrer; Grety Rihs; Jaroslav Kalvoda; Mihailo Lj. Mihailović

Publisher
John Wiley and Sons
Year
1989
Tongue
German
Weight
982 KB
Volume
72
Category
Article
ISSN
0018-019X

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✦ Synopsis

Dedicated to Dr. Gunther OhlofTon the occasion of his 65th birthday (7.11.89) Thermolysis of steroidal 5~,8a~peroxides of type 3a-d generates as major products the corresponding diseco compounds containing a 14-membered ring instead of the standard A-B-C-ring skeleton. Depending on the reaction conditions, either the primary products of type 9 or the a;punsaturated ketones of type 4, formed by subsequent elimination of AcOH, are isolated. The latter, configurationally uniform compounds undergo epoxidation of the C( 9)=C(10) bond followed by a Baeyer-Villiger oxidation to give, as final products, the 15membered cyclic epoxyenol lactones of type 20 and 21. The structures of the various products were determined by 'Hand "C-NMR spectroscopy. The conformations of the 14-and 15-membered rings were established by Xray structure analyses of 7 and 21a. A reaction mechanism for the above transformations is discussed.

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