X-ray crystal structures and conformational analysis of bicyclo[5.3.1]undec-1(11)-enes: Twisting versus pyramidalization in anti-Bredt olefins

Citation
Gw. Wijsman et al., X-ray crystal structures and conformational analysis of bicyclo[5.3.1]undec-1(11)-enes: Twisting versus pyramidalization in anti-Bredt olefins, J ORG CHEM, 66(4), 2001, pp. 1216-1227
Citations number
43
Categorie Soggetti
Chemistry & Analysis","Organic Chemistry/Polymer Science
Journal title
JOURNAL OF ORGANIC CHEMISTRY
ISSN journal
00223263 → ACNP
Volume
66
Issue
4
Year of publication
2001
Pages
1216 - 1227
Database
ISI
SICI code
0022-3263(20010223)66:4<1216:XCSACA>2.0.ZU;2-G
Abstract
The synthesis of several 9,11,11-trihalo[5.3.1]propellanes and their 4-dime thylsila analogues is described. They solvolyze under formation of the corr esponding isomeric 7,9,11-trihalobicyclo[5.3.1]undec-1(11)-enes which are " anti-Bredt" olefins with a strained trans double bond in a bridged eight-me mbered ring; in the presence of nucleophiles such as water or ethanol, the corresponding 7-hydroxy or 7-ethoxy derivatives, respectively, are obtained . On the basis of the X-ray crystal structures of four of these compounds ( la, 9a, 15, 17b), the effect of strain and of the substitution pattern on t he degree of twisting and pyramidalization of the double bond is discussed.