Photochemical [2 + 2] cycloaddition reactions of 6-alkenyl-3-phenylcyclohex-2-en-1-ones: using biradical conformation control to account for exceptions to the "rule of five"
Item Type:Journal Article
Citation:Stephen A. Bradley, Brian J. Bresnan, Sylvia M. Draper, Niall W. A. Geraghty, Mark Jeffares, Thomas McCabe, T. Brian H. McMurry and John E. O'Brien, Photochemical [2 + 2] cycloaddition reactions of 6-alkenyl-3-phenylcyclohex-2-en-1-ones: using biradical conformation control to account for exceptions to the "rule of five", Organic and Biomolecular Chemistry, 47, 12, 2011, 2959 - 2968
document(14).pdf (Published (publisher's copy)) 661.2Kb
A series of 6-alkenyl-3-phenylcyclohex-2-enones has been synthesised and the structures of the products obtained from them on irradiation have been determined. The 6-propenyl compounds afforded a tricyclic `parallel? [2 + 2] cycloaddition product and a bicyclic enone resulting from hydrogen abstraction in the biradical intermediate. The 6-butenyl and 6-pentenyl analogues gave `crossed? cycloaddition products only. Although the regiochemistry of these cycloaddition reactions cannot be explained in terms of the `rule of five?, it is compatible with the concept of `biradical conformation control? which is based on a consideration of the energy and structure of the possible 1,4-biradical intermediates.
Author: DRAPER, SYLVIA MARY
Type of material:Journal Article
Series/Report no:Organic and Biomolecular Chemistry;
Availability:Full text available