A forbidden rearrangement.
[reaction: see text] A barrelene derivative fragments to afford benzene and trappable 1,2,3-tricyanocyclopropene. The barrelene anion fragments more easily to liberate benzene and the 1,2,3-tricyanocyclopropenyl anion, which is not trappable or stable in solution. However, the major thermal product from the barrelene anion is a rearranged allyl anion that is formed by disrotatory cleavage of the cyclopropyl ring, a formally Woodward-Hoffmann-forbidden process. Several proposals are offered to rationalize this forbidden rearrangement.
Leivers
Martin
M
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Tam
Iris
I
Groves
Kevin
K
Leung
David
D
Xie
Yuli
Y
Breslow
Ronald
R