Tetracyclo decane

The tetrahydroquinones referred to above are readily reduced to tetrahydro-l-naphthoquin-4-ol derivatives, the photochemistry of which is also of interest. In solution these materials, 117, undergo intramolecular (2 + 2) photocycloaddition to give products, 118, having the tetracyclo[5.3.0.02-604 2]decane ring skeleton. If their configuration permits, these products immediately convert into hemiacetals, 119. 

Preference for the cleavage of the C3-C4 bond was observed for the hydrogenolysis of bishomocubanes.40-43 In an effort to synthesize barettane and dihydrobarettane, the hydrogenation of the bishomocubane bis(dimethyl acetal) 12 a over 10% palladium on charcoal at 119 atmospheres in methanol produced in quantitative yield tetracyclo[5.2.1.02-6.04,8]decane-5,10-dione bisfdimethyl acetal) (13a). Similar hydrogenation of bishomocubane bis(ethylene acetal) 12b in ethanol afforded tetracyclo[5.2.1.02-6.04,8]decane-5,10-dione bis(ethylene acetal) (13b), also in quantitative yield.42... 

One type of Wurtz reaction that is quite useful is the closing of small rings, especially three-membered rings.1250 For example, 1,3-dibromopropane can be converted to cyclopropane by Zn and Nal.1251 Two highly strained molecules that have been prepared this way are bicyclobutane1252 and tetracyclo[3.3.1.13 TO - decane.1253 Three- and four-membered... 

Dihydrofulvalene (368) has been reported to enter into Domino Diels-Alder cycloaddition with dimethyl acetylenedicarboxylate to give an ca 1 1 mixture of the polycondensed diesters 502 and 503 (Scheme 74).352,354,417 These products can be most readdy separated by selective saponification of the less hindered isomer. Both molecules contain the fundamental a//-c/s-tetracyclo[7.2.1.04 11.06, l0]do-decane nucleus but with an additional bond across the central portion. In 502, this linkage can be cleaved by a number of methods to produce appreciably more func-... 

Tetracyclo[4.3.1,03-1 °.0 -1 ° decan 4-Hydroxy-2-methoxycarbonyl-E17e, 321 (2-N2 —1-oxo —cyclopen tan - COOR —cyclobutan) Tricyclo 4.2.2.02,5ldecan 4-Acetoxy-... 

It also proved possible to modify the structures of the diphenyldiazomethane adducts 11 and 13 in the syntheses shown of ex o-3,3-diphenyl-8-methylenetricyclo[3.2.1.0 ]octane (12) and 9,9-diphenyl-cxo-tetracyclo[4.2.1 .0 ]decan-aMn -10-ol (14) (in this special case the Grignard reagent was used for solvolysis). 

It is noteworthy that irradiation of tetracyclo[6.2.0.0 . 0 ]decan-9-one resulted in cycloreversion and formation of ketene and vinylcyclopropane tricyclo[5.1.0.0 ]oct-5-ene instead of ring cleavage and decarbonylation. A C-C double bond a to a cyclopropane ring also resulted when spiro bicyclo[2.2.1]hept-5-ene-7,l -cyclopropane -2-one eni/o-epoxide underwent a deep-seated rearrangement upon irradiation through Corex to give 5-oxo-spiro[2.4]hept-6-ene-4-ylacetaldehyde in 50% yield. ... 

Similar reactions of tetracyclo[4.2.1.P . 0 ]decane afforded ring-cleaved products containing the tricyclo[4.2.1.1 ]decane skeleton. These rearrangements are analogous to the cleavage reactions of bicyclo[2.1.0]pentane, and related compounds. ... 

Salt crystals of the benzonorbornadiene carboxylic acid 68 with optically pure triplet sensitizer amines 70, 71 also underwent enantioselective di-TT-meth-ane photorearrangement to afford the optically active tetracyclo[5.4.0.0 ". 0 ]un-decane derivative 69 in high enantiomeric excess [81]. The 4-acetylbenzyl ester of L-phenylalanine 70 and the 4-benzoylphenyl ester of l-valine 71 perform the dual roles of asymmetric induction and triplet energy sensitization. 

The C oH 4 saturated stabilomer has been conHrmed experimentally (46) (AlBrs isomerization) as tetracyclo(5.2.1.0 -. 0 ]decane in agreement with the calculations. A considerable number of tetracyclodecanes have been calculated and are included in Table 17. 

Tetracyclo[4.2.1.0/ 0 ]decane undergoes a retro 2 + 2 cycloaddition at high temperatures (325°C) in contrast to the same reaction of [2.2.2]propellane which reacts at room temperature (see Chapter 9, Section 4) (Scheme 11.98)/ ... 

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