Bicyclo nonane 5- cyclooctene

Auf analoge Weise erhalt man galvanostatisch (200 mA) aus 5-Oxo-cycloocten 1-Hydroxy-bicyclo[3.3.0 pctan (69% d. Th.) bzw. aus 2-[Buten-(3)-yl]-cyclohexanon 1-Hydroxy-9-methyl-bicyclo[4.3,0]nonan (67% d. Th.)2 ... 

Introduction of the allene structure into cycloalkanes such as in 1,2-cyclononadiene (727) provides another approach to chiral cycloalkenes of sufficient enantiomeric stability. Although 127 has to be classified as an axial chiral compound like other C2-allenes it is included in this survey because of its obvious relation to ( )-cyclooctene as also can be seen from chemical correlations vide infra). Racemic 127 was resolved either through diastereomeric platinum complexes 143) or by ring enlargement via the dibromocarbene adduct 128 of optically active (J3)-cyclooctene (see 4.2) with methyllithium 143) — a method already used for the preparation of racemic 127. The first method afforded a product of 44 % enantiomeric purity whereas 127 obtained from ( )-cyclooctene had a rotation [a]D of 170-175°. The chirality of 127 was established by correlation with (+)(S)-( )-cyclooctene which in a stereoselective reaction with dibromocarbene afforded (—)-dibromo-trans-bicyclo[6.1 0]nonane 128) 144). Its absolute stereochemistry was determined by the Thyvoet-method as (1R, 87 ) and served as a key intermediate for the correlation with 727 ring expansion induced... 

The enthalpy of formation of ( )-cyclooctene and of tran.s-bicyclo[6.1.0]nonane were taken from the semiprimary/semiarchival reference for enthalpies of hydrogenation and of formation, W. R. Roth, O. Adamczak, R. Breuckmann, H.-W. Lennartz and R. Boese, Chem. Ber., 124, 2499 (1991). As with References 3 and 14-17, we maintain the practice of generally citing archival sources rather than the original reference. 

Transannular hydride shifts, first detected by Cope and coworkers in solvolyses of cyclooctene oxide, have subsequently been found in a number of related systems, e.g. cyclooctadiene monoepoxides, CA o-bicyclo[3.3.1 ]non-2-ene epoxide and l-oxaspiro[2.6]nonane. In general these reactions do not involve skeletal rearrangements, and they will not be discussed in detail. 

In refluxing cyclooctene, exo-7-bromo-c t/f>-7-(trimethyistannyl)bicyclo[4.1.0]heptane (20) reacted via the corresponding cyclopropylidene intermediate to afford spiro[bicyclo[4.1.0]hep-tane-7,9 -bicyclo[6.1.0]nonane] (21) in 76% yield. However, this reaction is not preparatively interesting and not applicable to a-bromo-a-(trimethylstannyl)cyclopropanes in general, because the cyclopropylidenes from the latter gave ring-opened allenic products. ... 

A methodically related transformation, the copper(Il)-mediated transfer of a cyano(ethoxycar-bonyl)methylene unit from ethyl cyanoacetate to alkenes, is presented in Section I.2.I.2.4.2.9. The copper-mediated synthesis of cyclopropyl ketones from a,a-dibromo ketones and alkenes seems to be of very limited scope and even less efficient than the corresponding synthesis of cyclopropanecarboxylic acids from o ,a-dibromoacetates (vide supra). The reaction (toluene, 100°C, 93 h) of cyclooctene (4.0 mmol), dibromomethyl phenyl ketone (8.0mmol), and commercial grade copper powder (18 mmol) activated with iodine (0.2 mmol) gave exy-9-benzoyl-bicyclo[6.1.0]nonane (7, 12%) and (2-oxo-2-phenylethyl)cyclooct-l-ene (8, 3%). ° A similar treatment of styrene gave l-benzoyl-2-phenylcyclopropane in only 2% yield [ratio (cisjtrans) 1 l.b]. " ... 

A screening of ruthenium(II) carboxylates and several ruthenium(II) chloride complexes has identified tetrakis(trifluoroacetato)diruthenium as an excellent catalyst for the cyclo-propanation of cyclooctene with ethyl diazoacetate (60°C, excess of alkene, 0.75 mol% of catalyst yield of ethyl bicyclo[6.1,0]nonane-9-carboxylate 99% endojexo 1.65)." With several other ruthenium(II) complexes, ring-opening metathesis polymerization of cyclooctene competes strongly with the cyclopropanation reaction. 

Polymerization of Bicyclo[n. 1.0]Alkanes. From the large-ring bicyclo[n.l.0]alkane series, six were chosen because of their relative ease of synthesis bicyclo[5.1.0]octane (M2), bicyclo[6.1.0]nonane (M3), bicyclo[ 10.1.0] tridecane (M4), and the corresponding 1-methylbicyclo-[n. 1.0] alkanes and prepared from the corresponding cycloalkenes or 1-methylcyclqalkenes (cycloheptene, cyclooctene, and cyclododecene). See Equation 4. 

Corey, E.J. and Shulman, J.I., The direct synthesis of optically active trans-cyclooctene. Optically active tra s-bicyclo[6.1.0]nonane. Tetrahedron Lett., 3655-3658,1968. 

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