HETEROLYTIC FRAGMENTATION OF YL-DELTA(2)-DEHYDRO-QUINIUCLIDINE-2,3-DICARBOXYLIC ACID-ESTERS

The title quinuclidines undergo cleavage under the action of acids or H2O to give Delta(2)-dehydro-4-piperidones 4, 5 and isobutylene; the r esulting redistribution of bond lengths upon N-protonation has been de monstated by X-ray diffraction methods for picrate 2a as well. as by a b initio calculations for quinuclidine 1a, cation 2a' and zwitterion 2 a '', the latter being the most suitable as an intermediate of the fra gmentation.