Octa-2,6-diene

Dienes can undergo olefin metathesis reactions of two types (i) intermolecular and (ii) intramolecular, as illustrated by the reactions of hexa-1,5-diene and octa-1,7-diene, equations 27 and 28, respectively. 

Benzo-2-aza-bicy clo 3.3.0]octa-1,7-dien 3,3-Dimethyl-5-hydroxy- -2-oxid E14b, 1474 (aus Nitro-keton)... 

Fig. 15 Structures of copolymers of isoprene/hexa-1,5-diene (a) and isoprene/octa-1,7-diene (b)...

Octa-1,7-diene 24/19 Octadiene monooxide(48) Octadiene dioxide (7)... 

Cross-metathesis reactions between undeuterated and deuterated dienes, such as octa-1,7-diene (Grubbs 1976) and 2,2 -divinylbiphenyl (Katz 1976b) have also been studied as a means of testing the metal carbene mechanism. The initial proportions of ethene-tfo, -d2, and -d4 formed in these reactions support this mechanism. Likewise for the cross-metathesis between c/5,cw-deca-2,8-dienes... 

Octa-1,7-diene has been a favourite molecule for testing catalytic activity and for carrying out labelling experiments, because reaction (2) is generally highly selective. The reaction of 1 1 mixtures of normal and 1,1,8,8-J4-octa-1,7-diene gives ethene, the isotopic composition of which 4/2 d/ corresponds closely to... 

The failure of cyclohexene to give high polymer is due to its low strain energy, — AH being too small to offset the positive value of — TAS. However, at low T and high [M] it is possible to obtain a small proportion of oligomer see Section 12.4.1. The reverse reaction, namely the elimination of cyclohexene from molecules in which two double bonds are separated by five single bonds, occurs readily, for example, in the intramolecular metathesis of octa-1,7-diene and of deca-2,8-diene. 

As discussed in Section 11.2.1, the polymerization of cyclohexene does not occur because of its very low strain energy. For the same reason, cross-metathesis of cyclohexene with acyclic olefins is strongly disfavoured. Nevertheless, using a high pressure of ethene, it is possible to displace the equilibrium sufficiently to be able to detect a trace of octa-1,7-diene product (Crain 1972). Likewise a small yield of dodeca-1,7-diene may be detected in its reaction with hex-l-ene (Bykov 1994) and of undeca-2,8-diene in its reaction with pent-2-ene (Herisson 1971). 

Alternatively, <7,(7 excited states of simple cyclobutanes seem to be accessible on 185-nm excitation The quantum yields are = 0.12 for substrate consumption and Op = 0.10 and Op = 0.03 for the formation of octa-1,7-diene and cyclohexene . Similarly, cubane (55) decomposes on 185-nm excitation with a quantum yield of O = 0.08 to give cyclooctatetraene and benzene (equation 24). 

Treatment of octa-1,7-diene with monochloroborane under high-dilution conditions gave a mixture of polymer and chloroborane (76), which was treated with methanol and dichloromethyl methyl ether to give cyclo-octadecane-l,10-dione (6 % isolated). Tetradeca-1,13-diene was similarly converted into cyclopentadecanone (7% isolated). ... 

France R, Short R, Dawson R. Attachment of human keratinocytes to plasma co-polymers of acrylic acid/octa-l,7-diene and aUyl amine/octa-1,7-diene. J Mater Chem 1998 8 37-42. 

Components 1. C5H12, Cyclohexane [110-82-7] 2. CsHi4, Octa-1,7-diene [3710-30-3] ... 

The complex cw-[(OC)4Mo CNMeCH2CH2NMe 2] has been shown to be catalytically active in methylmethacrylate polymerization, and weakly active in the metathesis of octa-1,7-diene. Reactions of pentacarbonyltungstendi-phenylcarbene with cyclic enol ethers have been studied in a series of papers. ... 

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