Accession Number : AD0710326

Title :   STUDIES IN RING EXPANSION.

Descriptive Note : Final scientific rept. 1 Jan 67-30 Jun 70,

Corporate Author : GLASGOW UNIV (SCOTLAND) DEPT OF CHEMISTRY

Personal Author(s) : Buchanan,G. L. ; Jamieson,G.

Report Date : 30 JUN 1970

Pagination or Media Count : 22

Abstract : The bridge-scission of a bicyclo(5,3,1)undec-8-en-11-one to a cyclodecene derivative, by Beckmann rearrangement of the oxime, fails because the resulting amide cannot be hydrolysed. This is due to movement of the double bond into the bridgehead - i.e. the failure of Bredt's Rule - which limits the scope of this synthetic route. In order to explore the limits of Bredt's Rule, the anti-Bredt alpha-beta-enones, bicyclo(5,3,1)undec-7(8)-en-11-one and bicyclo(5,3,1)undec-7(11)-en-8-one, as well as some derivatives of these systems, have been synthesised and examined, chemically, spectroscopically and in one instance by X-ray crystallography. The strain in these molecules is found to lead to bond-angle deformation and twisting about the C=C; the conjugation is also interrupted by twisting about the central bond of the enone. Evidence has been found to support the recent suggestion that a bridge-head double-bond lying within the single-carbon bridge of a bicyclo(5,3,1)undecene is more strained than one lying within the three-carbon bridge. The deviation of alpha-beta-enones from planarity is calculable by an empirical relationship. (Author)

Descriptors :   (*CYCLOALKANES, CHEMICAL REACTIONS), (*KETONES, CHEMICAL REACTIONS), SYNTHESIS(CHEMISTRY), CHEMICAL BONDS, ALKENES, AMIDES, GREAT BRITAIN

Subject Categories : Organic Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE