1,1,10,10-Tetrabromo paracyclophane

Fourfold Heck coupling (twofold on each dibromobenzene moiety) and Jeffery conditions has been applied on the two easily accessible tetrabromo[2.2]paracyclophane isomers 21 and 23, respectively, to prepare new double-layered 1,2- and 1,4-distyrylbenzene chromophoric systems 22-R and 24-R respectively, to enable studies of intramolecular charge-transfer phenomena in such systems (Scheme... 

Scheme 11 Two twofold Heck couplings of 7,8,15,16-tetrabromo[2.2]paracyclophane-7,15-diene 25. ...

Dibenzo[2.2]paracyclophane-1,9-diene (2), a unique molecule with two parallel sets of mutually orthogonal aromatic rings, was first synthesized in 1985 by Wong et al. [18]. The reported five-step synthesis gave the strained hydrocarbon in only 0.5% yield. Later a more versatile and economic approach to dibenzoannelated [2.2]paracyclophanedienes 11 including the parent compound 2 was developed by de Meijere et al. [19]. The dibromo[2.2]paracyclo-phane-l-ene (6) and the tetrabromo[2.2]paracyclophane-1,9-diene (7) were obtained from commercially available [2.2]paracyclophane (1) in a bromination-dehydrobromination reaction sequence. With compounds 6 and 7 available in large quantities, the palladium catalyzed coupling with alkenes (Heck reaction)... 

Scheme 3. Bromination - dehydrobromination sequence giving l,2-dibromo[2.2]paracyclo-phane-l-ene and 1,2,9,10-tetrabromo[2.2]paracyclophane-l,9-diene [19a]...

Fig. 13 Preparation of pseudoortho dibromide, a tribromo compound, and step and cross tetrabromo[2.2] paracyclophanes...

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