Tetraenes Octatetraenes

In Figure 21, attention is directed to a molecule for which identical modules are bound to non-overlapping halves of a ring. Cahn and Dermer [45], name this compound trans-p-(l-4-r 5-8-r -cyclo-octatetraene)- bis-(tricarbonyliron). Godwin [46], on the other hand, recognizes that there is the possibility for connections to only some of the atoms and thus elects to include all relevant locant numbers namely p-(l,2,3,4-r - 5,6,7,8-T -cycloocta-l,3,5,7-tetraene)- bis-(tricarbonyliron). In the nomenclature being developed in this... 

The three reported preparations " of tricarbonyI(cyclo-octatetraene)iron involve the interaction of cycloocta-tetraene with iron pentacarbonyl. Although the yields arc good, considerable amounts of CgHg[Fe(CO)3]2 and CgHsFe2(CO)7 are often obtained as well. The reaction betw cen cyclooctatetraene and triiron dodecacarbonyl takes place more rapidly and gives a product of better purity. 

On warming the solution of (LIV) and the phosphine, the green color rapidly disappeared and the products obtained were the octaphenylcyclo-octatetraene (XLIII) and the bis(tert-phosphine)palladium chloride (LXX). (XLIII) presumably arises from the tricyclooctadiene which is formed by coupling of the diradical (LXXI). The ligand-exchange reaction based on this has already been described in Section IV, F none of the cydoocta-tetraene (XLIII) was formed here (59). 

Cyclo-octatetraene.—Synthesis. Full details have been published on the preparation of stable cyclo-octatetraene bond-shift isomers. 1,2,3,8-Tetramethylcyclo-octa-tetraene was prepared from sulphone (140) by dialkylation, reduction, bromination, and dehydrobromination and shown to give Diels-Alder adduct (141 = H,... 

Alternatively, they can be prepared from cyclo-octatetraene and the finely divided metals [127]. X-ray powder diffraction data indicate that these complexes are isomorphous with uranocene. In a similar manner, bis(cyclo-octa-tetraene)protactinum has also been synthesized [134] ... 

The reaction of cyclo-octatetraene dianion with a variety of esters and anhydrides is reported with ethyl oxalate at — 60°C the tetraene (287) is obtained, via 7,8-disubstituted cyclo-octa-l,3,5-triene, whereas with ethyl acetate the product is (288). ... 

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