Bicyclo 3.2.11-2-octene

The thermal isomerization of this compound has been studied in both gas and liquid phases (Branton et al., 1965). The compound is more stable than the corresponding bicyclo-octene but does isomerize to... 

Until very recently no serious exceptions to Rule 2b, regiospecificity, were reported. The report of Miller (77) that cyclobutanones fused to bicycloheptene and bicyclo-octene skeletons do not lead to major products expected from cleavage at the most substituted a-carbon, represents a serious violation of Rule 2b. 

Hydrogen abstraction on irradiation of the ketone (361) results in formation of a series of bicyclo-octenes. ... 

The optically active endo-bicyclo-octene aldehyde (800), prepared by standard reactions from (798) via (799), is converted on u.v. irradiation into the cyclic ether (801) which can be reductively cleaved regiospeciGcally with LiAlH4 in JV-methylmorpholine to the alcohol (802). Net reduction of the alcohol (802) was achieved by the standard sequence (802)- (803)- (804). The final hydrocarbon product, (+)-twistbrendane (804), is in effect a nortwistane chiroptical data confirms (804) to be the enantiomer of the previously prepared (—)-twistbrendane. ... 

COT is prepared by the polymerization of ethyne at moderate temperature and pressure in the presence of nickel salts. The molecule is non-planar and behaves as a typical cyclic olefin, having no aromatic properties. It may be catalytically hydrogenated to cyclo-octene, but with Zn and dil. sulphuric acid gives 1,3,6-cyclooclairiene. It reacts with maleic anhydride to give an adduct, m.p. 166 C, derived from the isomeric structure bicyclo-4,2,0-octa-2,4,7-triene(I) ... 

Bei der Elektrolyse von 1-Acetyl-naphthalin in 2 n athanol. Kalilauge wird 59% d.Th. 9-Methyl-9-naphihyl-( 1 )-6-acetyl- (benzo-6-oxa-bicyclo[3.2.1 ]octen-(2)) erhalten2 ... 

Jones and Vogel investigated the snbstitnent effect of a 5,6-bis(methoxycarbonyl) group in bicyclo[2.2.2]octene (48i) [117]. The substituent effect of a single 5-exo substituent on the facial selectivities of bicyclo[2.2.2]octenes 48b-48h was also characterized by our group [118]. Epoxidation and dihydroxylation of the olefin moiety of 5-exo-substituted... 

The HOMOs of unsubstituted vinylidenenorbomane 47a and unsubstituted bicyclo[2.2.2]octene 48a are intrinsically comprised of similar components, i.e., the n orbital of the ethylene and the o-orbitals of the ethano bridges, the coupling being in an out-of-phase fashion (50 and 51), though the arrangement of the components is different. The contour plot (49) of the HOMO of 48a is consistent with these orbital interactions (50). 

As discussed in connection with the facial selectivities of 7-methylidenenorbom-ane 46 and bicyclo[2.2.2]octene 48, the components of the molecules, i.e., n functionality and two interacting o orbitals at the two P positions, are the same, but the connectivity of these fragments, i.e., the topology of the n systems, is different (A and B, Fig. 9). A similar situation was found in the case of spiro[cyclopentane-l,9 -fluorene] 68 [96, 97] and 11-isopropylidenedibenzo-norbomadienes 71 (see 3.4.1 and 3.4.2) [123]. In these systems, the n faces of the olefins are subject to unsymmetrization due to the difference of the interacting orbitals at the P positions. In principle, consistent facial selectivities were observed in these systems. 

Recently a reverse perturbation effect of a cyclopropyl group on facial selectivities was described in two bicyclic systems, bicyclo[2.2.2]octane 59 and norbomane (bicyclo[2.2.1]heptane) 60 [124]. Bicyclo[2.2.2]octene 59a, annulated with an exo-cyclopropyl group, i.e., exo-tricyclo[3.2.2.0 ]non-6-ene, and 7-methylenenor-bomane 60a, annulated with an exo-cyclopropyl group, i.e., 8-... 

The i yn-preference of 59a is concluded to be attributable to the fused cyclopropyl ring, based on the observation that the bicyclo[2.2.2]octene (59b) fused with a... 

This structural analysis was later confirmed by Komatsu and co-workers who prepared two new series of dehydroannulenes fused with bicyclo-[2.2.2]octene moieties [58]. In the series of compounds 17-20 (Fig. 2), they showed by X-ray crystallography that trimeric 18 has a planar n-electron peri-... 

Scheme 2.201. Synthesis of c/s-bicyclo[3.3.0]octenes via domino carbolithiation/ electrocyclization/electrophile trapping.

Ring-opening was not restricted just to norbornenes bicyclo[3.3.0]octenes, cyclooctene and a functionalised cyclobutene were all reactive substrates for these reactions. 

Condensed Aromatic Hydrocarbons Annelated with Bicyclo[2.2.2]octene Frameworks... 

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