Norbornadiene, reaction+carbonyls

Copolymerization to form polyketones proceeds by the carbonylation of some alkenes in the absence of nucleophiles. Copolymerization of CO and norbornadiene takes place to give the polyketone 28(28]. Reaction of ethylene and other alkenes with CO affords the polyketones 29. The use of cationic Pd catalysts and bipyridyl or 1,10-phenanthroline is important for the polymerization [29-31]. 

The carbonylation of norbornadiene in benzene solution catalyzed by PdCl2 leads to the formation of a polymeric ketone.532 This unusual reaction is believed to have the complex [PdCl2(nbd)] as its catalyst precursor, and the mechanism proposed for it is given in Scheme 47. 

Iodophenol has been carbonylated in the presence of norbornadiene to give a reasonable yield of coumarin, which is formed by a spontaneous retro Diels-Alder reaction from the initially formed product (equation 158)891. 

It was also discovered that the exo-isomer was formed exclusively in the reaction (except in cases involving norbornadiene where the formed exoisomer underwent irreversible isomerisation to the entfo-isomer, catalysed by dicobalt octacarbonyl) and noted when the products are derived from unsymmetrical acetylenes (MeC=CH or PhC=CH) only a single position isomer is isolated... it is readily shown that the single substituent always occurs on the carbon atom adjacent to the carbonyl group , 3... 

With c, 6 days at 60- 70°C is necessary to complete the reaction. Sulfur reacts with b to form the thiophosphathiirane, metal carbonyls give rjl complexes, and with norbornadiene the Diels-Alder adduct is... 

Schrauzer and Thyret have described (528, 529, 531) the synthesis of olefin-Ni(O) complexes containing a quinone, in particular, duro-quinone, as a ligand. The red, diamagnetic duroquinone complexes are obtained by reaction of nickel carbonyl with the quinone in excess olefin. They are stable in air and soluble in polar organic solvents and water. Those olefins which form the coiiqilex contain essentially parallel double bonds, e.g., norbornadiene, dicyclopentadiene, 1,5-cycloocta-diene, 1,3,5-cyclooctatriene, or cyclooctatetraene. 

In a number of cases, alkenes that are too unstable for isolation have been isolated in the form of metal complexes. As example is norbornadienone, which was isolated in the form of its iron-tricarbonyl complex (13), where the norbornadiene unit is an p" ligand, and each of the carbonyl units are ligands. The free dienone spontaneously decomposes to carbon monoxide and benzene (see reaction 17-28). 

The simple carbonyl complexes 89 have recently been prepared indirectly by reactions of benzo[c]cinnoline with norbornadiene metal complexes... 

Palladium-catalyzed carbonylative addition reactions of 2-iodophenols 3 to norbornadiene lead to coumarin systems 4 via stereoselective cis-exo addition and retro-Diels-Alder elimination of cyclopentadiene12, l3. Intramolecular versions of this reaction type have been reported34 35, which include the use of nickel36-42-4 3 and rhodium3 catalysts. 

Ethene complex 339 is much more prone to ligand exchange reactions than carbonyl complex 327. Treatment with the bidendate ligands 1,5-cyclooctadiene, bis(diisopropylphosphanyl)ethane, 2,2 -bipyridyl, and norbornadiene at 20 °C results in the formation of unchelated complexes 336 and 340—342 in 82—93% yield no irradiation is necessary ° (Chart 18). 

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