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Die Cope-Umlagerung als Prinzip einer repetierbaren Ringerweiterung


Bruhn, Jens; Heimgartner, Heinz; Schmid, Hans (1979). Die Cope-Umlagerung als Prinzip einer repetierbaren Ringerweiterung. Helvetica Chimica Acta, 62(8):2630-2654.

Abstract

The Cope Rearrangement, a Reaction for Repeatable Ring Expansions - Starting with the unsaturated beta-ketoesters of type I, a vinyl group is introduced into the beta-position by 1,4-addition of vinyl magnesium chloride to give II (Scheme 3). Treatment of the beta-ketoester II with phenyl vinyl sulfoxide in the presence of sodium hydride yields the sulfides III, which on thermolysis lead to the alpha,beta-divinyl ketoesters of type IV via elimination of sulfinic acid (Scheme 3). The Cope-System IV undergoes rearrangement to V, which is again an unsaturated beta-ketoester. The latter is suitable for a further ring expansion sequence. These reaction steps were carried out with the nine-, twelve- and fifteen-membered ketoesters 32, 33 and 34, as well as with the open-chain compound 35 (Table 1). With the cyclohexane derivative 31, ring expansion could not be achieved with the described sequence.

Abstract

The Cope Rearrangement, a Reaction for Repeatable Ring Expansions - Starting with the unsaturated beta-ketoesters of type I, a vinyl group is introduced into the beta-position by 1,4-addition of vinyl magnesium chloride to give II (Scheme 3). Treatment of the beta-ketoester II with phenyl vinyl sulfoxide in the presence of sodium hydride yields the sulfides III, which on thermolysis lead to the alpha,beta-divinyl ketoesters of type IV via elimination of sulfinic acid (Scheme 3). The Cope-System IV undergoes rearrangement to V, which is again an unsaturated beta-ketoester. The latter is suitable for a further ring expansion sequence. These reaction steps were carried out with the nine-, twelve- and fifteen-membered ketoesters 32, 33 and 34, as well as with the open-chain compound 35 (Table 1). With the cyclohexane derivative 31, ring expansion could not be achieved with the described sequence.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:German
Date:1979
Deposited On:12 Aug 2014 15:58
Last Modified:08 Dec 2017 06:49
Publisher:Wiley-Blackwell
ISSN:0018-019X
Funders:Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung

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