Nenitzescu’s hydrocarbon

The process is induced photochemically and involves the single-electron transfer oxidation of cubane then completed with a backward electron transfer to the transient radical cations. A Li+ salt with a weakly coordinating anion is able to induce pericyclic transformations, including the rearrangement of cubane to cuneane, quadricyclane to norbomadiene, and basketene to Nenitzescu s hydrocarbon 392... 

Doering, W. von E., and J. W. Rosenthal 9.10-Dihydronaphthalene. Formation from bullvalene and Nenitzescu s hydrocarbon, thermal reorganization, and photorearrangement to bullvalene. J. Amer. chem. Soc. 88, 2078 (1966). 

Two adducts 20 and 21 were obtained with Nenitzescu s hydrocarbon 19 as the diene, resulting from homo-Diels-Alder and 1,3-dipolar cycloadditions, respectively the adduct 21 is the substrate in an alternative route to the hydrocarbon snoutene. ... 

Oxidative bisdecarboxylation. An efficient recent synthesis of Nenitzescu s hydrocarbon (3) involves a Diels-Alder reaction followed by bisdecarboxylation with this Ni complex. Pb(OAc)4 is unsatisfactory for the latter step. The product (3) was also used for preparation of barrelene (4) in 24% yield from (1). 

Basketene to iyn-Tricyclo[4.4.0.0 ]deca-3,7,9-triene to Nenitzescu s Hydrocarbon... 

This, however, was just the beginning of the interconversions. Only two other isomers were known prior to 1966, namely, tricyclo[4.2.2.0 ]deca-3,7,9-triene or Nenitzescu s hydrocarbon (NHC) and triquinacene (TRQ) (Scheme 11.12). 

Syntheses have been reported of barrelene (505) and of Nenitzescu s hydrocarbon (503) on a reasonable scale and without some of the difficulties that attend the previously published routes." " The preparation of (503) is of central importance, it being obtained by the oxidative bisdecarboxylation of the cyclo-octatetraene-maleic anhydride Diels-Alder adduct (502) with dicarbonylbis(triphenylphosphine)-nickel in diglyme at reflux. Cycloaddition of (503) to 2,5-dimethyI-3,5-diphenyl-cyclopentadienone in hot benzene afforded (504) and its endo-isomer. Photolysis of (504) yielded (505) in 24% yield from cyclo-octatetraene. The thermally labile benzene-maleic anhydride [4 + 2] cycloadduct (506) was obtained in similar fashion from (502). A review of the mechanisms of pyrolysis of (503) and a number of isomers and benzo-fused (CH) derivatives (collectively termed Nenitzescu s hydrocarbons) has appeared." ... 

A more efficient synthesis of Nenitzescu s hydrocarbon has been described.The synthesis uses the addition of acryloyl chloride (rather than maleic anhydride) to cyclo-octatetraene, and degradation of the adduct by standard methods. 

Vedejs and have studied the thermolysis of Nenitzescu s hydrocarbon... 

An improved procedure for the Diels-Alder reaction between cyclo-octatetraene and dimethyl acetylene dicarboxylate to give dimethyl unti-tricyclo[4,2,2,0 ]deca-3,7,10-triene-7,8-dicarboxylate (85 %) has been described. Diels-Alder reactions of maleic anhydride and mono-substituted (Mr, CHjOAc, Ph, CO2CH3. OMe, cyclopropyl substituents) and di-substituted (Me, Me CHjOAc, CHjOAc —(CH2)4— Me, CH2 O Ac substituents) cyclo-octatetraenes have been described cyclopropyl cyclo-octatetraene was obtained from bromocyclo-octatetraene and cyclopropyl lithium. The Diels-Alder reaction between cyclo-octatetraene and acryloyl chloride which gives a mixture of endo- and exo-adducts (80% total yield), was the first step in a reported synthesis of Nenitzescu s hydrocarbon. ... 

Details for the preparation of (872) gave appeared. " The synthesis of 6-methylene-2(6H) zulenone derivatives has been achieved, but the methides are so reactive that they could be isolated only in the form of the [4 -l- 4] dimers (873). A new synthesis of Nenitzescu s hydrocarbon (874), suitable for a large scale preparation, has been described. The dibenzo-analogue of (874) has been prepared. ... 

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