Tricyclo nonanes

Methyl-l-phenyl- -4,4-dioxid 653 2,4,6-Trioxa-tricyclo[3.2.1.11 7]nonan... 

Trichloroacetyl fluoride, 45, 6 2-(Trichloromethyl)bicyclo[3.3.0]octane, from reaction of chloroform and cib,o i-l,5-cyclooctadiene, 47,10 hydrolysis with phosphoric acid to c.ro-m-bicyclo[3.3.0]octane-2-carboxylic acid, 47, 11 1,1,3-Trichloro- -nonane, 46,104 Tricyclo[2.2.1,02 6]heptan-3-ol, 46,... 

Thiocarbonyl tetrachloride, i6, 21 Thionyl chloride, 45, 16, 98 Thiophosgene, 45, 21 Thiophosphoryl chloride, reaction with methylmagnesium bromide to yield tetramethylbiphosphine disulfide, 45,102 Toluenesulfonybromide, 46, 88 Trichloroacetyl fluoride, 46, 6 1,1,3-Trichloiio- -nonane, 46,104 Tricyclo[2.2.1.0 ]heptan-3-ol, 45,... 

The construction of the tricyclo[5.2.0.02,6]nonane (26, n = 1) and tricyclo[6.2.0.02,7]decane (26, n = 2) frameworks involved the [2 4- 2] cycloaddition of readily accessible31,32 l,2-bis(trimethyl-siloxy)cyclobutene and cnone 25, n = 1 or 2, respectively.33 The yields (75-80%) were good for adducts 26a, c, e, and g. Lower yields (40-50%) were observed for adducts 26b and 26f, while adduct 26d was only isolated in a trace amount. The most interesting and important reaction, related to the total synthesis of eudesmane sesquiterpenes, was the photochemical reaction of (-)-piperitone (25g) with l,2-bis(trimethylsiloxy)cyclobutene, which gave c/.v,(5wf/u W-2/j,7/i-dimethyl-4/ -isopropyl-l f ,8Jf -bis(triniethylsiloxy)tricyclo[6.2.0.0z 7]dec-3-one (26g) with the relative cis configuration of the methyl (R2) and isopropyl (R3) groups.33,34 Some of the other photochemical [2 + 2] cycloaddition reactions utilizing l,2-bis(trimethyl-siloxy)cyclobutene are shown by the formation of 2735,36 and 28.37... 

Methyl anfi-Tricyclo(3.2.1.12 4)nonane- ,n4o-3-carboxylate Typical Procedure 33... 

Photolysis of rraHs-4,5-dibrorno-c.vfl-9,10-diazatricyclo[6.3.0.02 7]undec-9-ene (21, R = H) gave ra s-4,5-dibromo-c v >-tricyclo[6.1.0.02 7]nonane (22, R = H) as the major product.95 However, significant amounts of both stereoisomers of fratts-4,5-dibromo-l-methylenc-2-vinyl-cyclohexane (23, R = H) were also formed. 

Selenium dioxide oxidation of dimethyl 3-oxo-tjxo-tricyclo(4.2.1.02 5]nonan-fw/o,< i3V>-7,8-di-carboxylate gave dimethyl 3,4-dioxo-< vo-tricyclo[4.2.1.02 5]nonane-em/o,e rfo-7,8-dicarboxy-late.107... 

This transformation was first explored by treatment of l-bromo-4-(cyanomethyl)pentacyclo-[4.3.0.02 5.03-8.04-7]nonan-9-one ethylene acetal (61) with lithium diisopropylamide in tetrahy-drofuran at 0 °C, which resulted in almost quantitative yield of an inseparable mixture of two alkenes to which the structures l-bromo-4-cyanomethyltricyclo[4.2.1.02,5]nona-3,7-dien-9-one ethylene acetal (66) and l-bromo-4-(cyanomethylene)tricyclo[4.2.1.02,5]non-7-en-9-one ethylene acetal (67) were assigned.170,171 As illustrated below, the overall cage-degradation reaction can be mechanistically represented by the stepwise C —C bond fission reactions, whose driving force can be attributed to the apparently substantial reduction in cage constraint. 

In agreement with this mechanism, it was found that the epoxide (4RS)-4,4-(epoxy-methano)tricyclo[5.1.0.02,5]octane-e c/o-8-carbaldehyde 2,2-dimethylpropaneT,3-diyl acetal (1) gave 4-oxotricyclo[6.1.0.02,6]nonane- ,/ttreatment with lithium iodide in tetrahydrofuran.71 Several examples employing this oxaspirohexane to cyclopentanone isomerization method are shown (see Table 7).69-80 Lithium bromide in the presence of hexamethylphosphoric triamide was also effective in these transformations.70,74,76 79,80... 

One of the most interesting types of polycyclic carbon compounds prepared in recent years is the group of tricyclic substances known as propellanes. A typical example is tricyclo[3.2.2.0 -5]nonane, which sometimes is called [3.2.2]propellane, 12. The physical properties of several of these are included in Table 12-6. A quick look at formula 12 probably does not suggest any great structural difference from the bicyclic compounds we have discussed previously. However, if one tries to construct a ball-and-stick model of 12, one soon concludes that the propellanes are truly extraordinary substances in that all four carbon bonds at the bridgehead carbons extend, not to the comers of a tetrahedron, or even a distorted tetrahedron as for a cyclopropane ring, but... 

Einen direkten Weg zu Derivaten des cis-verknupften Bicyclo [3,2,0]-heptans stellt die analoge photochemische Addition von Maleinsaureester an Cyclopenten dar (195). Produkte mit trans-Verkniipfung der 4- und 5-Ringe werden nicht gebildet. Die unsensibilisierte Photoaddition von Maleinsauredimethylester an Norbomen fiihrt ausschlieBlich zum exo-Tricyclo[4,2,l,02.5]nonan-Derivat (143). 

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