Stereo- and regioselectivity in dynamic gas-phase thermoisomerization (DGPTI): novel route to alpha-campholanic acid and derivatives.
[reaction: see text] Dynamic gas-phase thermoisomerization (DGPTI) of (-)-2-phenylisoborneols effects stereo- and regioselective ring opening under formation of (+)-trans-alpha-campholanic acid derivatives. Similarly, (-)-alpha-2-phenylfenchol underwent under DGPTI conditions ring opening to (-)-fencholic acid derivatives. In both cases, DGPTI led to cleavage of the weakest bond in the isomeric bicyclic structures. A reaction mechanism involving a diradical intermediate is supported by a deuterium labeling study.
Rüedi
Georg
G
Organisch-Chemisches Institut der Universität, 8057 Zürich, Switzerland. georg@access.unizh.ch
Nagel
Matthias
M
Hansen
Hans-Jürgen
HJ