STUDIES IN RING EXPANSION.
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 1970
- Accession Number
- AD0710326
Entities
People
- G. Jamieson
- G. L. Buchanan
Organizations
- University of Glasgow