Acid-Catalysed Backbone Rearrangement of cholesta-6,8(14)-dienes

Acid-Catalysed Backbone Rearrangement of cholesta-6,8(14)-dienes

Rearrangement of 5α‐ and 5β‐cholesta‐6,8(14)‐dienes (13a and 13b, resp.) in the presence of anhydrous toluene‐4‐sulfonic acid in acetic acid leads to 5α‐ and 5β‐12(13 → 14)‐abeo‐cholesta‐8,13(17)‐dienes (15a and 15b, resp.) via 5α‐ and 5β‐cholesta‐8,14‐dienes (14a and 14b, resp.), respectively. Epim...

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Veröffentlicht in:Helvetica chimica acta 1996-06, Vol.79 (4), p.989-998
Hauptverfasser: Liu, Rong-Ming, Chillier, Xavier F. D., Kamalaprija, Philippe, Burger, Ulrich, Gülaçar, Fazil O.
Format: Artikel
Sprache:eng
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Zusammenfassung:Rearrangement of 5α‐ and 5β‐cholesta‐6,8(14)‐dienes (13a and 13b, resp.) in the presence of anhydrous toluene‐4‐sulfonic acid in acetic acid leads to 5α‐ and 5β‐12(13 → 14)‐abeo‐cholesta‐8,13(17)‐dienes (15a and 15b, resp.) via 5α‐ and 5β‐cholesta‐8,14‐dienes (14a and 14b, resp.), respectively. Epimerization at C(20) of the spirosteradienes 15a and 15b occurs with increasing reaction time. Molecular‐mechanics calculation of the relative stabilities of these compounds and of congeners thereof is in agreement with the observed reaction pathway.
ISSN:0018-019X
1522-2675
DOI:10.1002/hlca.19960790407