Syntheses and Properties of Dichlorodimethyltetradehydro-trideca-, -pentadeca-, -heptadeca-, -nonadeca-fulvene, and Benzannelated Pentadecafulvene Derivatives

Article abstract of DOI:10.1039/P19830002997

Syntheses of 13-dichloromethylene-4,9-dimethyl-5,6,7,8-tetradehydrocyclotridecene (18), 15-dichloromethylene-4,9-dimethyl-5,6,7,8-tetradehydrocyclopentadecene (19), 17-dichloromethylene-6,11-dimethyl-7,8,9,10-tetradehydrocycloheptadecene (20), and 19-dichloromethylene-6,11-dimethyl-7,8,9,10-tetradehydrocyclononadecene (21) are described.Examination of the 1H n.m.r. spectra indicates that all of these fulvene are atropic.Syntheses of benzannelated derivatives of (19), i.e. 7-dichloromethylene-13-methyl-14,15,16,17-tetradehydrobenzocyclopentadecene (28), 9-dichloromethylene-13-methyl-14,15,16,17-tetradehydrobenzocyclopentadecene (29), and 7-dichloromethylene-16,17,18,19-tetradehydrodibenzocyclopentadecene (39) are also described.The influence of the dichloro substitution at the exocyclic bond of fulvene, and of benzannelation on the structure of tetradehydropentadecafulvene, is discussed on the basis of the 1H n.m.r. and u.v. spectra of these fulvene as well as those of the corresponding diphenyl substituted derivatives.