Cyclooctene, -: synthesis

Scheme 3 Dienophiles for tetrazine bioorthogonal reaction and corresponding second-order rate constant, a 7>ani-cyclooctene synthesis and rate constant comparison, b Bicyclononyne as a dienophile. c Recently reported dienophile mini-tags and their corresponding rate constant. 2 was measured by reacting with tetrazine 14 was measured by reacting with tetrazine 15 2 was measured by reacting with tetrazine 16...

Ashworth IW, Miles JAL, Nelson DJ, Percy JM, Singh K. Trisubstituted cyclooctene synthesis at the limits of relay ring-closing metathesis a racemic difluorinated analogue of fucose. Tetrahedron. 2009 65(46) 9637—9646. 

Scheme 8.20 Cyclooctene synthesis through Rh-mediated four-carbon ring expansion.

Scheme 8.22 Cyclooctene synthesis through Re-catalyzed two-carbon ring expansion.

Inoue, Y., Takamuku, S., and Sakurai, H., Direct cis-trans photoisomerization of cyclooctene. A convenient method for preparing Irans-cyclooctene, Synthesis, 111, 1977. 

Scheme 22 Efficient cyclooctene-forming diene-ene RCM, facilitated by cyclic constraint in Paquette s total synthesis of asteriscanolide (116) [75]...

Scheme 23 Improved formation of cyclooctene ring with second-generation catalyst C in Paquette s total synthesis of teubrevins G (122) and H (123) [76]...

These studies paved the way for numerous synthetic applications, in particular total syntheses. Thus, the low-tech PtCl2, PtCl4, or PtBr4 systems, as named by Fiirstner, proved superior and more reliable compared to Trost s TCPCtfe system288 for the reactions of the cyclooctene substrate as shown in Scheme 81.300 These reactions, which could be run in a multi-gram scale, proved useful, for instance, for the formal total synthesis of streptorubine B. Similarly, a formal total synthesis of roseophilin was devised, based on a nearly quantitative transformation of an enyne moiety into a bicyclic diene system (Scheme 81).301... 

The cyclooctene complex was first isolated and adapted to cluster synthesis by Shapley and co-workers (156). The complex is formed by reaction of ethylene with H2Os3(CO)10 in cyclooctene, when only a trace of the vinyl adduct HOs3(CO)10-CH=CH2 is formed. The 13C-NMR spectrum indicates that substitution by the olefin of equatorial carbonyl groups on two different metal centers has occurred. The complex... 

A new class of heterogeneous catalyst has emerged from the incorporation of mono- and bimetallic nanocolloids in the mesopores of MCM-41 or via the entrapment of pro-prepared colloidal metal in sol-gel materials [170-172], Noble metal nanoparticles containing Mex-MCM-41 were synthesized using surfactant stabilized palladium, iridium, and rhodium nanoparticles in the synthesis gel. The materials were characterized by a number of physical methods, showed that the nanoparticles were present inside the pores of MCM-41. They were found to be active catalysts in the hydrogenation of cyclic olefins such as cyclohexene, cyclooctene, cyclododecene, and... 

Further important industrial applications of olefin metathesis include the synthesis of 3,3-dimethyl-l-butene ( neohexene , intermediate for the production of musk perfume) from ethene and 2,4,4-trimethyl-2-pentene, the manufacture of a,co-dienes from ethene and cycloalkenes (reversed RCM), and the ROMP of cyclooctene and norbomene to Vestenamer and Norsorex , respectively. 

Cyclooctene gives dimethyl octanedioate under these conditions. Scheme 12.18 illustrates some cases in which ozonolysis reactions have been used in the course of synthesis. 

Emrick and Coughlin et al. reported on the synthesis of cadmium selenide-polymer composites. A vinylbenzyl-derivatized phosphine oxide was ph-ysisorbed onto cadmium selenide particles. Subsequent reaction with RUCI2 (PCy3)2(CHPh) or RuCl2(NHC)(PCy3)(CHPh) (NHC= 1,3-dimesityhmidazol-2-ylidene) followed by addition of cyclooctene, 7-oxanorborn-5-ene-2,3-dicarboxylic anhydride, dicyclopentadiene or N-methyl-7-oxanorborn-5-... 

Scheme 5.2-6 Synthesis of a deuterated analogue of the square-planar Ni-complex (t -4-cycloocten-l-yl](l,5-diphenyl-2,4-pentanedionato-0,0 )nickel for H NMR investigations.

The Pd-catalyzed intramolecular aminocarbonyiation has also been applied to the formal total synthesis of Anatoxin-A 219, an acetylcholine mimic (Equation (16)). Thus, the reaction of 5-(methoxycarbonylamino)-cyclooctene 216a in the presence of a catalytic amount of PdCl2 and cupric chloride (CUCI2) (3 equiv.) in methanol under ambient pressure of CO gave the desired azabicyclo[4.2.1]nonane 217 as the predominant product. The regioselectivity of this reaction is highly dependent on the nature of the A -substituent. Thus, the... 

The ruthenium catalyst can be used to catalyze the synthesis of a cyclic poly(octenamer). The catalyst is added to ris-cyclooctene in CH2CI2 solution at 45° C. The intermediate macrocyclic complex undergoes an intramolecular chain transfer to yield the cyclic polymer and regenerate the catalyst. 

Since reactivity of alkenes increases with increasing alkyl substitution, hydration is best applied in the synthesis of tertiary alcohols. Of the isomeric alkenes, cis compounds are usually more reactive than the corresponding trans isomers, but strained cyclic isomeric olefins may exhibit opposite behavior. Thus, for example, frans-cyclooctene is hydrated 2500 times faster than cw-cyclooctene.6 Similar large reactivity differences were observed in the addition of alcohols to strained trans cycloalkenes compared with the cis isomers. frans-Cycloheptene, an extremely unstable compound, for instance, reacts with methanol 109 faster at —78°C than does the cis compound.7... 

The synthesis of polyoctenamer has been commercialized by Huels.150 In contrast with the transformation of cyclooctene to 1,9-decadiene [Eq. (12.31)], homogeneous catalyst compositions, such as WClg + EtAlCl2, are used to promote ring-opening metathesis polymerization of cyclooctene. A polymer of narrow molecular-weight distribution with high trans content (55-85%) called Vestenamer is produced and used as blend component in different rubbers and thermoplastics. 

Vic-diols can thus be easily converted to alkenes through their reaction with A, A -thiocarbonyldimidazule. The reported synthesis of trans-cyclooctene is illustrative of the method [219]. It should be noted that continuous elimination of rrans-cyclooctene by a stream of argon was necessary to avoid isomerization to the cis isomer. The conversion of cis-cyclooctene to ww-cyclooctene through a trithiocarbonate is described in the same paper. 

The reactivity of carbonyl clusters can be enhanced substantially by the use of their activated derivatives which contain such labile ligands as acetonitrile, ethene, or cyclooctene. For example, it was the synthesis of acetonitrile derivatives Os3(CO)12 x(NCMe)x (x = 1,2)1 that spurred the development of the chemistry of this trinuclear cluster.2-4 In general, the reactions of the activated clusters occur under mild conditions and result in high selectivities and yields. 

Cyclic allenes have been obtained in high yields, as illustrated by the synthesis of 1,2-cyclononadiene from the dibromocarbene adduct of the readily available cyclooctene (equation 51).138 The smallest stable cyclic allene known to date is (14) it was prepared from the dibromocyclopropane (13) in high yield.139 A small amount of the tricyclic compound (15) was also obtained (equation 52). The cyclic allene (14) did not undergo dimerization even on prolonged standing at ambient temperatures. In contrast, the unsubstituted analog was detected only at -60 °C by H NMR. It should also be noted that cyclohexa-1,2-diene was generated by the reaction of methyllithium on dibromobicyclo[3.1.0]hexane and trapped as the Diels-Alder adduct.160... 

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