Stepwise Introduction of π-Electron Cross-Conjugation: A Possible Access to [5]Radialenes?
作者:Florence Geneste、Alec Moradpour、Georges Dive
DOI:10.1021/jo970107d
日期:1997.8.1
As starting points to the stepwise access to the corresponding [5]radialene, the unsaturated esters 14a and 18a have been prepared. These compounds have been isolated along with their isomers 14b and 18b, resulting from an intracyclic double-bond migration. Moreover a subsequent base-catalyzed process mediated the total isomerization of these mixtures to the latter more stable compounds 14b and 18b. The energy contents of the various compounds, and the corresponding tri- and tetrasubstituted higher homologues 19 and 20, have been calculated at the ab initio level, using several minimal as well as extended basis sets, and the observed experimental results rationalized.