3 Paracyclophane-1,9,17-triene,

A novel example of a 3,5-disubstituted 1//-azepine is methyl 12-azabicyclo[8.3.2]penta-deca-l0,l3,14-triene- 2-carboxylate (6) obtained, albeit in low yield, by the action of basegenerated (methoxycarbonyl)nitrene on [8]paracyclophane (5).147... 

The configurations of the bicyclo[6.2.2]dodeca-l(10),8.11-trienes (]6]-paracyclophanes) 12 and ent-12 were determined by correlation with the corresponding oxabicyclo[6.3.2]trideca-l(ll),8,12-trienes (3,6-hexanooxepines) (/>)-10 and (AZ)-IO of known configuration (for assign-... 

Rehybridization would partially displace the intraanular tr-electron density to the outside of the benzene rings, thus reducing destabilizing interaction in the interior of the molecule. In addition, rehybridization rationalizes a striking feature of the triene 6, also found in [2.2]paracyclophane 112 its diene 72V> and in [3.3]paracyclo-phane20 the aromatic C—H-bonds of all phane hydrocarbons mentioned are inclined towards the inside of the molecule, e.g. in triene 6 by an angle of 13°. 

Vapor phase thermolysis of [6]paracydophane (la) (Structures 1) yielded spiro triene 77 (Structures 10) as the major product via homolytic cleavage of one of the benzylic bonds [5b, 10]. FVP of [5.2.2]propelladiene (21a) (Structures 3) afforded spiro compound 78 (Structures 10) by similar homolysis of intermediate [5]paracyclophane (2a) (Structures 1) [61]. In contrast, the reverse reaction, FVP of spiro trienes, was successfully used for the preparation of [n]paracy-clophanes with n = 7 and 8 [62]. Pyrolysis of spiro tetraene 79, however, did not give [7]paracycloph-3-ene (80) (Structures 10) [63]. Evidently, [7]paracy-clophane is the borderline case with regard to the thermodynamic stabilities between the bridged aromatic compound and the spiro triene isomer. 

CiaHanNiOa, 1,5-Cyclooctadiene-duroquinone-nickel, 30B, 323 Cl9H1gCrOa, Tricarbonyl(3-8-T -[2.2]paracyclophane)chromium, 44B, 777 CigHiBCrOi, Ethyl-phenyl-o-methylbenchrotrenylmethanol, 39B, 634 Cl 9H19Mn, (r -Methylcyclopentadienyl) (T -7-exo-phenylcyclohepta-1,3,5-triene)manganese, 44B, 777... 

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