Tricyclo octane derivatives from

A detailed comparison of the rearrangement of 1,3-radicai cations and carbocations derived from tricyclo [3.3.0.0 " ] octanes has shown (by eiectron-transfer oxidation and protonation, respectiveiy) that electronic substituent effects on the diyi sites profoundly influence the regioseiectivities of the Wagner-Meerwein 1,2-shifts. The... 

The reduction of a series of bicyclic and tricyclic ketoximes using both Na-ethanol and LAH has been carried out and the product mixtures analyzed in detail. In this investigation it was found that reduction of the oximes derived from two tricyclo[2.2.1.0 ]heptan-3-ones (87) and (88) with either LAH-THF or Na-ethanol gave mixtures of exo (89) and (90) and endo (91) and (92) amines. Neither method of reduction was particularly stereoselective and the yields were somewhat better with LAH (87 76% versus 67% and 88 67% versus 44%). In contrast, reduction of the oximes of three bicyclo[2.2. l]heptan-2-ones (93)-(95) with LAH-THF gave significant quantities of azabicyclo[3.2.1]octanes (96)-(98) in addition... 

In contrast to norbornadiene, bicyclo[2.2.2]octa-2,5-diene does not always give the transan-nularly bridged products in normal solution reactions, whereas in the anodic electrooxidation this nonconjugated octadiene showed the formation of products, mainly tricyclo-[2.2.2.0 ]octane derivatives 5 and 6 from transannular interaction, exclusively. ... 

The C-NMR parameters for trachylobane and C-19 derivatives were consistent with predicted values derived from 9-methyl-/ra/i5-decalin and tricyclo[2.2.1.0 ]octane 21). 

As an alternative to a radical chain mechanism for this bromination, a cationic mechanism has been proposed for the reaction between 48 and A-bromosuccinimide. It involves attack of bromine at C6 of 48 leading ultimately to the cyclopropylmethyl cation A. This cation is a bromo derivative of tricyclic cyclopropylmethyl cation, which has been shown to be the common intermediate in the solvolysis of esters of tricyclo[3.2.1.0 ]octan-3-ol, endo- and exo-tricyclo[3.2.1.0 ]octan-4-ol and of cxo-bicyclo[3.2.1]oct-2-en-7-ol. It has been shown that under long-lived ion conditions at — 78 C such cations are the most stable species that are formed from bicyclo[3.2.1]oct-2-en-3-ol and from bicyclo[3.2.1]octa-2,6-dienes. In kinetically controlled reactions, which are postulated to proceed via cyclopropylmethyl cations a tendency can be seen towards formation of products retaining the cyclopropane ring. This case is achieved through loss of one of the protons at C4 of A. 

Diazo-compounds can in turn be generated photochemically from sodium salts of toluenesulphonyl hydrazones. Irradiation of the cyclobutane tosylhydrazone (44) gave trans-tricyclo[5.1.0.0 ]-octane (45 R=Me) by the pathway shown in Scheme 4 44 the tricycle (45 R=H) can also be obtained by photoelimination of nitrogen from the diazatricyclo[ 5.2.1.0 4]decene (46). The unexpected conversion of the anthracenocycloheptatriene derivative (47) into triptycene with loss of one carbon atom was observed on irradiation in tetrahydrofuran 4 the mechanism of this unusual reaction remains obscure and merits further investigation, but neither 1-triptycenyl nor 2-triptycenyl carbene appears to be an intermediate in this transformation. 

Numerous new examples of cyclopentenone synthesis from acetylenehexacarbonyl-dicobalt complexes and norbornene derivatives have been disclosed there is evidence of steric control, and the bulky trimethylsilyl group can be employed as a removable direction-determining group to allow synthesis of 3- instead of 2-sub-stituted cyclopentenones. Reaction of (731) with sodamide in toluene gave the new octahydro-2,5-methanoazulene system (732 R = CONHj) successive hydrolysis, reduction, and esterification converted (732 R = CONHj) into (732 R = CHjOTs) which, on solvolysis, gave the homoprotoadamantane derivative (733 X = H, R R = CH2) in high yield.The carboxylic acid (732 R = COjH) underwent spontaneous Friedel-Crafts intramolecular acylation on conversion into its acid chloride to give (733 XX = O R R = CHj) and (733 XX = O, R = Cl, R = Me). Reaction of methyl a-bromocrotonate (mixture of E- and Z-isomers) with the enolates of cyclohex-2-enone affords a mixture of stereoisomeric tricyclo-[3,2,l,0 ]octan-6-ones (734 R —R are variously H or alkyl) in moderate yield. The reaction involves double Michael addition and subsequent substitution. 

A high-yield synthesis of the norsemibullvalene derivative (724) has been reported reaction of (724) with methanolic potassium cyanide produces anti-7-cya.no-endo-5-bromonorbornan-2-one in high yield which indicates synthetic scope for stereoselective introduction of nucleophiles at C-7 of the norboman-2-one system. A one-pot synthesis of tricyclo[3,2,l,0 ]octan-6-ones of the type (725), by a bicyclo-annulation procedure from cyclohex-2-enones, has been achieved. " ... 

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