Bicyclo nonadiene

Dioxo-6-methyl-2-(2-carboxy-athyl)- 722 Bicyclo[4.3.0]nonadien-(3,7)... 

Diisobutylaluminium hydride catalyses the ring-closure of various dienes. It is proposed that the process involves addition of the aluminium hydride to a terminal double bond, followed by ring-closure and, finally, elimination of the catalyst (equation 106). Thus 1,5-hexadiene gives methylenecyclopentane (213) (equation 107), 1,6-heptadiene gives methylenecyclohexane (214) (equation 108), 4-vinylcyclohexene gives bicyclo[3.2.1]oct-2-ene (215) (equation 109) and the spiro compound 217 is obtained from 5-methylene-l,8-nonadiene (216) (equation 110)112. 

Reactions of methoxycarbonylformonitrile, furonitrile and substituted benzoni-trile oxides (4-Me, 4-OMe, 3-OMe, 4-C1, 3-C1, 2,4-di-Cl, 4-F as substituents) with dimethyl 7-(diphenylmethylene)bicyclo[2.2. l]hept-2-ene-5,6-dicarboxylate led exclusively to exo cycloadducts 82 (R = C02Me, 2-furyl, substituted phenyl), which, on irradiation with a low-pressure mercury lamp, afforded 3-azabicyclo [4.3.0]nonadiene-7,8-dicarboxylates 83 as the only products. The 1,3-dipolar cycloaddition, followed by a photorearrangement, provides a new method for obtaining tetrahydro-27/ -pyridine derivatives from cyclopentadiene (245). 

Based on a similar approach, Backvall403 established the stereochemical course of such reactions and developed efficient routes to bicyclo[4.3.0]-nonadiene and bicyclo[5.3.0]-decadiene systems. Backvall404 has also reported a Pd(02CCF3)2-catalyzed oxidative carbocyclization of allenenes (Scheme 125). The process is efficient even with catalyst loading as low as 1 mol%, although if requires/>-benzoquinone as the stoichiometric oxidant, which represents the first example of a C-C bond formation using a catalytic amount of Pd(ll). Bicyclic adducts have been obtained in... 

The metal-mediated and metal-catalyzed [6 + 2]- and [6 + 4]-cycloaddition reactions, pioneered by Pettit and co-workers105 106 and Kreiter and co-workers,107 respectively, involve the cycloaddition of metal-complexed cyclic trienes with 7r-systems such as alkenes, alkynes, and dienes. The [6 + 2]-reactions produce bicyclo[4.2.1]nonadiene derivatives and the [6 + 4]-reactions produce bicyclo[4.4.1]undecatrienes (Scheme 32). Trienes complexed to chromium, which can be prepared on large scale (40 g) as reported by Rigby and co-workers,108 react with 7r-systems upon thermolysis or irradiation.109-111 Chromium and iron-catalyzed [6 + 2]-reactions of cycloheptatrienes and disubstituted alkynes... 

When the pyrone 297 was exposed to base in dichloromethane, formation of the oxidopyrylium occurs and subsequent cycloaddition transpires. Lee found that when the allene tether was 3 (n = 0), cycloaddition occurs to form the bicy-clo[5.3.0]decadiene 298 exclusively, rather than the alternative bicyclo[5.2.0] nonadiene product 299. Increasing the tether length by one resulted in formation of the exo-substituted double bond (299) in 45% yield. Increasing the tether length by one carbon, to four, completely retarded the cycloaddition (Scheme 4.83). 

Bicyclic conjugated diene polymers were anionically prepared by Watanabe [ 1 ] using bicyclo[4.3.0]-2,9-nonadiene and bicyclo[4.3.0]-l,8-nonadiene and products used in high-performance resins. The polymer product of dicyclopenta-diene and 1,3-cyclohexadiene was also prepared by Oshima [2] and used in optical applications. 

Ether cleavage. Treatment of the keto ether (1,9-oxatricyclo[4.3.3.0]doUecane-3-one) with acetic anhydride and pyridine hydrochloride (reflux 5,5 hr.) yields the diacetatc (2, 4-acctoxy-l-(2-acetoxyethyl)bicyclo[4,3.0]nonadiene-4,6) in 93% yield. 

Several examples of isomerism of heavily substituted dienes into cyclobutenes have been reported. The reactions are brought about by the use of quartz filtered light. The reactions are quite efficient and, for example, the bicyclo[4.4.1]undeca-dienes (130) can be converted efficiently into the isomeric products (131) and (132) in the yields shown below the appropriate structure. Ring strain does not adversely affect the reaction since it is also possible to bring about ring closure of the bicyclo[4.2.1]nonadienes (133) to afford the tricyclic products (134) and (135). The (2+2)-photocycloaddition of the lambertianate derivative (136) results in the formation of the cyclobutane adduct (137). ... 

In the nickel(II) and cobalt(II)complexes of phosphabicyclo[3.3.1]nonanes 282 (246) and 283 (247), respectively, the bicyclo systems exist in a CC conformation according to X-ray data. Some complex compounds incorporating the bicyclo[3.3.1]nonadienes as ligands have been studied for example, X-ray data were reported for the platinum(II) complex 284 (248). 

Dimethyl-9-cyclobulm-(l)-yl-nonadien-(2,5) (IX) entsteht nur bei direkter Belichtung, exo- und endo-5-Methyl-l-vinyl-5-[4-m.ethyl-penten-(3)-yl]-bicyclo[2.1.1]hexan (VII, VIII)... 

Nooh selektiver auBert sich die Wellenlangenabhangigkeit bei cis-Bicyclo[4.3.0] nonadien- (2,4)3 ... 

Oxol2,13-dimethyl-(dibenzo-bicyclo J>.2.0] nonadien-(2,5)y-12,13-dicarbonsdure-anhydrid 57% d.Th. F 297-298°... 

Cycloaddition of allyl cations to conjugated dienes provides a route to seven-membered carbocycles. One of several methods can be used to generate the allyl cation, such as from an allyl halide and silver trifluoroacetate, or from an allyl alcohol by way of its trifluoroacetate or sulfonate. Cycloaddition of the allyl cation proceeds best with a cyclic diene, particularly for intermolecular reactions. Thus, cyclohexadiene and methylallyl cation gave the bicyclo[3.2.2]nonadiene 187 (3.125). Many intramolecular examples are known, such as the formation of the... 

Among a host of other phosphine-catalysed reactions in which the initial step is the formation of a reactive phosphoniobetaine intermediate by addition to a carbon-carbon double or triple bond are intramolecular cyclisations leading to benzobicyclo[4,3,0]-compounds, " cyclic ethers " and lactones,and a great many intermolecular reactions, e.g., a [3 -b 3]-annulation of modified t-butyl allylic carbonates and alkylidenemalonitriles to give cyclohexenes,phosphine- (and fluoride)- catalysed routes to 1,4-benzothiazepines from cyclic sulfenamides and alkynes, a [4- -3]-annu-lation of allylic carbonates with methyl coumalate to give functionalised bicyclo[3.2.2]nonadienes, the a-carbon addition of cyanide ion, generated in situ from cyanohydrins, to activated alkynes, and a stereoselective... 

However, Willcott found evidence for a radical chain process in these reactions. Thus,l,5-dimethyl-5-deuteriomethyl-CPD gives 23% do and 15% d2 product in addition to the expected di material. Nonetheless, spiro[4.4]nona-1,3-diene undergoes ring expansion to bicyclo[4.3.0]nonadienes with allowed retention of stereochemistry at the migrating carbon, so the reaction appears to be concerted in these cases (see Chapter 10, Section 3). 

Pyrolysis of exo- and /2Jo-tricyclo[4.2.1.0 ]nonadiene gives bicyclo[4.2.1]nona-triene with log = 14.2 - 44230/2.37 r and log = 14.68 - 40 550/2.3/ r, respectively, presumably by a forbidden disrotatory ring opening in each case (Scheme 10.21). Of interest is the fact that the remote double bond has little effect on the rate since the 7,8-saturated materials have similar activation parameters. 

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