The Michael Reactions of Chloro-substituted-9,9′-bifluorenylidenes with Fluorenes and a Comparison with Analogous Halogen Compounds

Abstract

The Michael reactions of 2-chloro- and 2,7-dichloro-9,9′-bifluorenylidenes with fluorenes were investigated. Structures of these products were confirmed by syntheses through the well-established reactions of 9-lithiofluorenes and 9-bromo-9,9′-bifluorenyls. The formation of some abnormal compounds is explained by intermediary formation of 2,7-dichloro-9,9′-bifluorenylidene from the reaction of 9,9′-bifluorenylidene with 2,7-dichlorofluorene as with the bromo-derivatives. The corresponding fluoro- and iodo-series gave predominantly normal addition products. These differences are explained in terms of the inductive and steric effects of the halogen substituents.

Cycloparaphenylene Lemniscates and Trefoils

“…The core unit of the lemniscates is a key element to their synthesis. The core of the alkene-linked lemniscates 2 has been prepared, both as the parent 12a and the necessary tetrachloro derivative , 12b . Compound 13 is close to the core of 5CC and 6CC .…”

9-Fluorenyl 9-(p-tolylsulfonyl)-9-fluorenyl disulfide: the unexpected product of the reaction of 9-bromofluorene and potassium p-toluenethiosulfonate and the mechanism of its formation

“…The evidence therefore points to 2 (R = 9-fluorenyl) and14 (R = [p-ClCeH4]2CH-) having structure 7. Both are 9-(p-tolylsulfonyl)-9-fluorenyl disulfides.…”

“…)-9-fluorenyl disulfide(14), mp 191-192 °C dec: DR(KBr) 1317 and 1140 cm"1 (S02); NMR (CDC13) 2.17 (s, 3 H), 5.55 (s, 1 H), 6.79 (d, 2 H), 6.93 (d, 2 ),7.21-7.56 (m, 14 ),8.11 (m, 2 H); 13C NMR (CDC13) 21.…”