1,5 -cyclooctadiene

A hydrocarbon that contains two double bonds is called an alkadiene, and the rela tionship between the double bonds may be described as isolated conjugated or cumu lated Isolated diene units are those m which two carbon-carbon double bond units are separated from each other by one or more sp hybridized carbon atoms 1 4 Pentadiene and 1 5 cyclooctadiene have isolated double bonds... 

Borabicyclo [3.3.1] nonane [280-64-8], 9-BBN (13) is the most versatile hydroborating agent among dialkylboranes. It is commercially available or can be conveniendy prepared by the hydroboration of 1,5-cyclooctadiene with borane, followed by thermal isomerization of the mixture of isomeric bicychc boranes initially formed (57,109). 

Catalytic Asymmetric Hydroboration. The hydroboration of olefins with catecholborane (an achiral hydroborating agent) is cataly2ed by cationic rhodium complexes with enantiomericaHy pure phosphines, eg, [Rh(cod)2]BE4BINAP, where cod is 1,5-cyclooctadiene and BINAP is... 

The reaction of a mixture of 1,5,9-cyclododecatriene (CDT), nickel acetylacetonate [3264-82-2], and diethylethoxyalurninum in ether gives red, air-sensitive, needle crystals of (CDT)Ni [12126-69-1] (66). Crystallographic studies indicate that the nickel atom is located in the center of the 12-membered ring of (CDT)Ni (104). The latter reacts readily with 1,5-cyclooctadiene (COD) to yield bis(COD) nickel [1295-35-8] which has yellow crystals and is fairly air stable, mp 142°C (dec) (20). Bis(COD)nickel also can be prepared by the reaction of 1,5-COD, triethylaluminum, and nickel acetylacetonate. 

A fascinating series of cyclodimeri2ation or cyclotrimeri2ation reactions was first observed in the labs of Wilke to produce 1,5-cyclooctadiene... 

A novel route to azelaic acid is based on butadiene. Butadiene is dimerized to 1,5-cyclooctadiene, which is carbonylated to the monoester in the presence of an alcohol. Hydrolysis of this ester foUowed by a caustic cleavage step produces azelaic acid in both high yield and purity (56). 

Rearrangements are also observed during halojluonnanons with cyclic medium ring dienes [70, 93] (equations 4 and 5) and with the monoepoxide of 1,5-cyclooctadiene [94] (equation 6) during halofluonnations Again, there are differences in product mixture with apparently minor variations in reagents (equation 4)... 

Interestingly, the intramolecular cycloadduct 97 (15%) was obtained from the reaction of 3,4-dicyanofuroxan with 1,5-cyclooctadiene. In contrast, with nor-bomadiene only intermolecular products 98 (30%) and 99 (14%) were obtained (85T727) (Scheme 48). 

Abbreviations Aik, alkyl AN, acetonitrile Ar, aryl Bu, butyl cod, 1,5-cyclooctadiene Cp, cy-clopentadienyl Cp , pentamethylcyclopentadienyl Cy, cyclohexyl dppm, diphenylphosphinome-thane dpme, Ph2PC2H4PMe2 Et, ethyl fod, 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octane-dionate HOMO, highest occupied molecular orbital LUMO, lowest unoccupied molecular orbital Me, methyl MO, molecular orbital nbd, norbornadiene Nuc, nucleophile OTf, triflate Ph, phenyl Pr, propyl py, pyridine THE, tetrahydrofuran TMEDA V,V,M,M-tetramethylethylenediamine. 

Abbreviations aapy, 2-acetamidopyridine Aik, alkyl AN, acetoniuile Ar, aryl Bu, butyl cod, 1,5-cyclooctadiene COE, cyclooctene COT, cyclooctatetraene Cp, cyclopentadienyl Cp , penta-methylcyclopentadienyl Cy, cyclohexyl DME, 1,2-dimethoxyethane DME, dimethylformamide DMSO, dimethyl sulfoxide dmpe, dimethylphosphinoethane dppe, diphenylphosphinoethane dppm, diphenylphosphinomethane dppp, diphenylphosphinopropane Et, ethyl Ec, feirocenyl ind, inda-zolyl Me, methyl Mes, mesitylene nb, norbomene orbicyclo[2.2.1]heptene nbd, 2,5-norbomadiene OTf, uiflate Ph, phenyl PPN, bis(triphenylphosphoranylidene)ammonium Pi , propyl py, pyridine pz, pyrazolate pz, substituted pyi azolate pz , 3,5-dimethylpyrazolate quin, quinolin-8-olate solv, solvent tfb, teti afluorobenzobaiTelene THE, tetrahydrofuran THT, tetrahydrothiophene tmeda, teti amethylethylenediamine Tol, tolyl Tp, HB(C3H3N2)3 Tp , HB(3,5-Me2C3HN2)3 Tp, substituted hydrotiis(pyrazol-l-yl)borate Ts, tosyl tz, 1,2,4-triazolate Vin, vinyl. 

An interesting addition reaction of sulfur dichloride has been discovered that allows the preparation in good yield of bridged cyclic sulfides from cyclic dienes. Two examples of the reaction have been described (cyclo-octadiene and in the other 1,5-cyclooctadiene. The former sequence is shown in the scheme. The experimental details of the latter sequence are given below. 

Cyclooctane Sulfide (9-Thiabicyclo[3.3.1]nonane) from 1,5-Cyclooctadiene... 

Photolytic reactions of dienes frequently give complex mixtures of rearranged products. Described here, however, is a photolytic isomerization of 1,5-cyclooctadiene (present in solution, in part, as a complex with cuprous chloride) that affords a good yield of one product. 

Boron trifluoride-acetic acid complex Harshaw Chemical Co., Allied Chemical Co. 1,5-Cyclooctadiene A, MCB Sulfur dichloride MCB Boron trifluoride etherate EK, MCB Mercuric acetate MCB Norbornene MCB Calcium carbide MCB Pinacol EK, MCB... 

Butadiene could be oligomerized to cyclic dienes and trienes using certain transition metal complexes. Commercially, a mixture of TiCU and Al2Cl3(C2H5)3 is used that gives predominantly cis, trans, trans-1,5,9-cyclododecatriene along with approximately 5% of the dimer 1,5-cyclooctadiene ... 

The most effective catalysts for enantioselective amino acid synthesis are coordination complexes of rhodium(I) with 1,5-cyclooctadiene (COD) and a chiral diphosphine such as (JR,jR)-l,2-bis(o-anisylphenylphosphino)ethane, the so-called DiPAMP ligand. The complex owes its chirality to the presence of the trisubstituted phosphorus atoms (Section 9.12). 

This two step procedure appears to be by far the most convenient one for preparing exo-ch-bicyclo[3 3 0]octane-2-car-boxylic acid from the readily available starting materials The first step of the procedure is also illustrative of the method of obtaining 2-substituted bicyclo[3 3 Ojoctanes4,6 from cis cn-1,5-cyclooctadiene. 

Benzoyl fluoride, 46,3 Benzoy lhydrazine, 46, 85 Benzoyl peroxide, as catalyst for reaction of chloroform with as,as 1,5 cyclooctadiene, 47, 11 reaction with diethyl ethylmalonate, 46, 37... 

Cyclic dienes and polyenes, monocyclic as well as bicyclic, can be metathesized in the same way as cyclic monoenes. As expected, cyclobutene 27), 1,5-cyclooctadiene, and 1,5,9-cyclododecatriene 28) yield the same polyalkenamer, in this case polybutenamer (1,4-polybutadiene), since these reactants consist of the same base units, i.e.—(CH2)2CH==CH— ... 

Mutual metathesis of a cyclic and an acyclic alkene provides still more possibilities in synthesizing organic compounds. For instance, cycloalkenes are cleaved by ethene into a,co-dienes. The reaction of 1,5-cyclooctadiene with ethene gives 1,5,9-decatriene (18) norbornene reacts with 2-butene to yield 1,3-dipropenylcyclopentane (30) ... 

Steric factors may also be important in situations where alternative modes of reaction are available. Dall Asta (44) examined the ring-opening polymerization of 3-methyl-m-cyclooctene. By infrared analysis of the product formed, he obtained quantitative information about the occurrence of head-to-head and head-to-tail successions. More than 90% of the links in the polymethyloctenamer were of the head-to-tail type, but the sterically more hindered and, therefore, unfavored head-to-head links were also observed (about 5%). Ofstead (39) investigated the ring-opening polymerization of some 1,5-cyclooctadienes substituted at one of the two... 

Cyclooctadiene, metathesis of, 135 stereoselectivity, 159, 160 Cyclooctene, metathesis of, catalysts for, 140... 

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