Octa-l,5-dien

Substituted derivatives of groups (1) and (2) above, e.g. 3-methylcyclo-butene and 1-methylcyclo-octa-l,5-diene. 

The major product is l,4-dimethyl-4-vinylcyclohexene together with smaller amounts of 1,6-dimethylcyclo-octa-l,5-diene, isoprene and 4-isopropenyl-1 -methylcyclohexene. 

Mechanistic studies of the equilibrium between cycloocta-1,5-diene (36) and 1,2-divinylcy-clobutancs (37)Vfi and between 2,3-dimethylenebicyclo[2.2.0]hexane (38) and bicy-clo[4.2.0]octa-l,5-diene (39)77 show the intermediacy of diradicals in these rearrangements. 

At 150 °C, the analogous 2-methylenetricyclo[4.1.0.01,3]heptane (34) equilibrated with 35 and 36 as products of a methylenecyclopropane rearrangement and a subsequent retro-Diels Alder reaction, respectively, until at 180 °C an irreversible rearrangement to bicyclo[4.2.0]octa-l,5-diene and 3,4-dimethylenehexa-l,5-diene (39) via diradical 37 took place.223,224 Increasing pressure favored the formation of the bicyclic system 38 (50% yield at lOOTorr).223... 

Vanhaelen, M., Vanhaelen, F. R. and Geeraerts, J. (1980). Occurrence in mushroom (Homobasidiomycetes) of d.v-ocla-1,5-dicn-3-ol and /nms-octa-l,5-dien-3-ol, attractant to the cheese mite Tyrophagus putrescentiae (Schrank) (Acarina, Acaridae). Experientia 36 406 107. 

OJFuR CmHm, Ruthenium(II), p-aqua-bis-(p-trifluoroacetato)bis[(T)J-cyclo-octa-l,5-diene)(trifluoroacetato)-, 26 254... 

Another type of bicyclo[3.3.0]octadienone formation is observed in the reactions of 4,4-gem-disubstituted 1,6-heptadiynes (353) with HSiMe2Bu-t catalyzed by Rh(acac)(CO)2 or Rh2Co2(CO)i2 under forced conditions, i.e. at 120 °C and 50 atm of CO, affording 7,7-disubstituted bicyclo[3.3.0]octa-l,5-dien-3-ones (354) in 71-95% isolated yields (equation 143)340,341. 

Direkte UV-Bestrahlung wandelt Cycloocta-l,3,5-trien (Formel 121) hauptsachlich in Bicyclo[4,2,0]octa-2,7-dien (Formel 122) und Tricyclo-[3,2,l,0a-8]oct-3-en (Formel 123) (58,222,340) um. Daneben werden noch all-trans-Octatetra-l,3,5,7-en (222) und Cyclo-octa-l,5-dien (58) nach-gewiesen. 

M. Green, A. Laguna, J. L. Spencer, and F. G. A. Stone, Bis(r -cyclo-octa-l,5-diene)-platinum and -palladium with Fluoroolefins, J. Chem. Soc., Dalton Trans. 1977, 1010-1016. 

R. Mackenzie, and P. L. Timms, Reaction of Metal Atoms with Solutions Preparation of Bis(cyclo-octa-l,5-diene)iron(0), J. Chem. Soc., Chem. Comm. 1974, 650-651. 

In a sample of defective wines, most in the barrel, half of them contained TCA or TeCA at clearly perceptible doses. Wines may also have defects described as earthy , weedy , wild mushrooms , wet cardboard and considerable research has centred on this. Lee and Simpson (1993) analysed them and identifieds compounds such as 2,4-dichloro-6-methylanisol, chlorated cresols, oct-l-en-3-one, oct-l-en-3-ol, d.y-octa-l,5-dien-3-one, d.y-octa-l,5-dien-3-ol, guayacol, 2-methyl-isoborneol and geosmine. Rapp (1992) also detected other substances in the corks such as 6-chlorovainilline, 4-chloro guayacol, 4,5-dichloro guayacol and veratrol. 

Olefinic complexes of copper have been reviewed in Volume 12 of this series (289). Since the appearance of this review, [Cu(cycloocta-l,6-diene)2]BF4 has been prepared by electrolysis of Cu(BP4)2 in methanolic diolefin at copper electrodes (231). Complexes (cycloocta-l,5-diene)Cu02C-CPg, (cyclooctatetrene)(Cu02C CPa)2, and (cyclo-octa-l,5-diene)(Cu02C CF3)a have been obtained as white or pale yellow solids by reacting CuOaC -CFg with the olefins in pentane or benzene, respectively (107). The structure of Cu2Gl2(trans-cyclooctene)3 (Fig. 10) has been determined (124) and is reminiscent of the structure of Cu2Cl2(PPh3)3 (Fig. 5). 

Cyclo-octa-l,5-diene reacts with diphenylacetylene to give a high yield of intramolecular reaction product of this 1 2 alkyne alkene type (equation 46) . ... 

Under an argon atmosphere methylenecyclopropane (8.0 g, 148 mmol) was added to (2,2 -bipyridine)(cyclo-octa-l,5-diene)nickel (2.98 g, 8.50 mmol) cooled to — 78°C. The violet suspension was warmed to — 30"C and stirred for 2 h at this temperature. A black precipitate was formed and the solution turned colorless. After filtration at — 78 °C, the filter residue was washed with EtjO (2 mL portions) until the color of the solution formed turned from violet to green. The remaining solid, after drying in vacuo (25°C/0.5 Torr), gave dark-green microcrystals yield 2.26 g (94%) dec. 140 °C. 

Volatile fungal metabolites contribute to the organoleptic properties of several other foodstuffs. Surface mould ripened cheeses such as Brie and Camembert are produced using Penicillium camembertii and, more commonly, P. caseicolum. Oct-l-en-3-ol accompanied by smaller amounts of octa-l,5-dien-3-ol and 3-one are major contributors to the aroma. These organisms also have the ability to produce 2-alkanones from fatty acids and these contribute to the odour of the cheese. 2-Methylisoborneol (7.70) and 2-methoxy-3-isopropylpyrazine (7.71) have been detected in mature cultures. An unpleasant earthy flavour encountered in some aged cultures has been attributed to the excessive produetion of 7.71. 

Anchored complexes on silica of the type —(PPh2) IrCl have been prepared and their ability to catalyse the hydrogenation of olefins and dienes was studied. The ability of anchored complexes to isomerize and hydrogenate cyclo-octa-l,5-diene has been investigated. The immobility of the bound PPh2 groups helps to keep the intermediate unsaturated. 

Rapp, A. and Knipser, W. (1979). 3,7-Dimethyl-octa-l,5-dien-3,7-diol- a new terpenoid component of grape and wine aroma, Vitis, 18,229-233. 

The rates of epoxidation of cyclododecene with a series of aliphatic peroxy-acids have been correlated, using the Taft equation. The reaction constant (p ) was + 2.0 and the steric constant (6) was found to be essentially zero. A two-parameter correlation has been found for the effect of basicity and polarity of the solvent on the rate of epoxidation of propene with peracetic acid. Rate constants and activation parameters for the epoxidation of a number of cycloalkenes, including (11 R = H or COOMe), (12 R = H, Ph, or 2-furyl), (13), (14), and cyclo-octa-l,5-diene, have been measured. An isokinetic relationship was demonstrated, with the isokinetic temperature of 3 C. There was only a weak dependence of the rate on the structure of the alkene. 

When the valence tautomer of cyclo-octa-l,5-diene (stable below —20 C) is treated with O2 under irradiation from a sodium vapour lamp (a street lamp), in the presence of tetraphenylporphyrin as sensitizer, the endo-peroxide (105) can be prepared in 85% yield. The endoperoxide serves as the starting material for three triepoxides (106), (107), and (108) (Scheme ). The structures of all three triepoxides have been confirmed by X-ray analysis. 

Two diaUcyl boranes arc in common use. The bicyclic 9-borabicyclo[3.3.1 ]nonane (9-BBN), introduced in Chapter 34 as a reagent for diastereoselective aldol reactions, is a stable crystaUine solid. This is very unusual for an alkyl borane and makes it a popular reagent. It is made by hydroboration of cyclo-octa-l,5-diene. The second hydroboration is fast because it is intramolecular but the third would be very slow. The regioselectivity of the second hydroboration is under thermodynamic control. 

A system for condensation of metal atoms into a cooled solution has been developed [390]. Condensation of iron vapour into a solution of cyclo-octa-1,5-diene in methylcyclohexane at —120°C yielded bis(cyclo-octa-l,5-diene)iron. 

Singlet oxygenation of cw,c -cyclo-octa-l,5-diene produces 6-hydroperoxy-cyclo-octa-1,4-diene and on further oxidation 5,8-dihydroperoxycyclo-octa-1,3-diene. Since reduction of this hydroperoxide with PhaP leads to cw-5,8-dihydroxy-cyclo-octa-1,3-diene, the whole sequence represents a convenient synthetic entry into 5,8-difunctionalized oxygen derivatives of cyclo-octa-1,3-diene. A highly stereoselective method has been developed for the cw-oxygenation of cycloheptyl systems. This involves irradiation of methanolic solutions of 1-acetoxy-cyclohepta-3,5-diene in the presence of haematoporphyrin as sensitizer to give... 

Reagents i, Bis(cyclo-octa-l,5-diene)nickel(0), PPh3... 

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