Tricyclo

Similarly, a brendane derivative (tricyclo[4.2.1.0 Jnonane) 141 was prepared in... 

The synthesis of adamantane (15), tricyclo[3.3.1.1 ]decane [281-23-2] by heating tetrahydrodicyclopentadiene (14) [6004-38-2] in the presence of aluminum trichloride illustrates another aspect of the synthetic utiHty of DCPD (80). Adamantane is the base for dmgs that control German measles and influenza (80-81) (see ANTIVIRAL AGENTS). 

CPD is the starting material for 8-hydroxymethyl-tricyclo[5.2.1.0 ] decane [57286-50-8] (16) (or octahydro-4,7-methano-lJT-indene-5—methanol), which is in turn converted into 3-halo-4-homoisotwistane (17), an intermediate for antiviral dmgs (82). 

The extension to polycycles with three or more rings is straightforward prefixes tricyclo-, tetracyclo-, etc. are used and the positions of the additional bridges are specified by superscripts (examples 59-61). 

Fig. 9.3. (A) Carbon framework from X-ray crystal stmcture of iyn-tricyclo[8.4.1.1]hexadeca-1,3,5,7,9,11,13-heptaene. (B) Side view showing deviation from planarity of aimulene ring. (Reproduced from Ref 60 by permission from the International Union of Crystallography.)...

Fig. 9.4. (A) X-ray crystal structure of j> n-tricyclo[8.4.1.F ]hexadeca-2,4,6,8,10,12,14-heptaene. iB) X-ray crystal structure of anti stereoisomer of tricyclo[8.4.1.1 ]hexadeca-2,4,6,8,10,12,14-heptaene-5-carboxylic acid. (Reproduced from Ref 63 by permission of Wiley-VCH.)...

The conversion of tricyclo-[4,4,0,0]-decan-4-one (237) into the moiiodeutera-ted hydrindanone (238) serves as a good illustration of this labeling proce-... 

The reaction of morpholine with tricyclo[2.2.1.0 ]hcptan-3-one (35) and with 5-bicyclo[2.2.1]hepten-2-one (36) does not proceed in the... 

The factors influencing ring size and conformation have not yet become clear. Thus, the yellow (MeAs)5 has a puckered Asj ring with As-As 243 pm and angle As-As-As 102° there is also a more stable red form. (PhAs)6 has a puckered Asg (chair form) with As-As 246 pm and angle As-As-As 91°. Numerous polycyclic compounds As R have also been characterized, for example the bright-yellow crystalline tricyclo-... 

A dry 5(X)-mI flask equipped with a thermometer, pressure-equalizing dropping funnel, and magnetic stirrer is flushed with nitrogen and then maintained under a static pressure of the gas. The flask is charged with 50 ml of tetrahydrofuran and 13.3 ml (0.15 mole) of cyclopentene, and then is cooled in an ice bath. Conversion to tricyclo-pentylborane is achieved by dropwise addition of 25 ml of a 1 M solution of diborane (0.15 mole of hydride see Chapter 4, Section 1 for preparation) in tetrahydrofuran. The solution is stirred for 1 hour at 25° and again cooled in an ice bath, and 25 ml of dry t-butyl alcohol is added, followed by 5.5 ml (0.05 mole) of ethyl bromoacetate. Potassium t-butoxide in /-butyl alcohol (50 ml of a 1 M solution) is added over a period of 10 minutes. There is an immediate precipitation of potassium bromide. The reaction mixture is filtered from the potassium bromide and distilled. Ethyl cyclopentylacetate, bp 101730 mm, 1.4398, is obtained in about 75% yield. Similarly, the reaction can be applied to a variety of olefins including 2-butene, cyclohexene, and norbornene. 

The reaction of oxepin with dimethyl 5-oxo-2,3-diphenylcyclopenta-l,3-diene-l,4-dicarboxy-late takes a different course. Two products 7 and 8 can be isolated, 7 is the [4 + 2] adduct of the cyclopentadienone across the central C-C double bond of the oxepin, the other, 8, is thought to be a [4+6] cycloadduct across the triene system of the oxepin.237 In boiling benzene, the [4 + 2] adduct 7 undergoes no cycloreversion, but rearranges to the tricyclo[5.3.02,4]deca-5,8-dien-10-one system.237 The [4+6] adduct, however, is stable under thermal conditions. 

A special method, with only two examples, starts from 1,2,4-triazines.20 21 Diels-Alder reaction with the strained dienophile dimethyl tricyclo[4.2.2.02,5]deca-3,7,9-triene-7,8-dicarboxylate (14) is followed by an elimination of nitrogen via a retro-Diels-Alder process. The formed product, however, cannot be isolated, but reacts via another retro-Diels-Alder reaction and an electro-cyclic reaction to provide the azocine derivative 15. The sequence order of the reactions is not clear, but both pathways lead to the same product. 

Cory and Renneboog53 have devised an efficient bicycloannulation for the synthesis of tricyclo[3.2.1.02,7]octane-6-one (66) as shown in equation 63. The method involves three steps (1) the enolate undergoes an initial conjugate addition to phenyl vinyl sulfone, (2) the resulting sulfone-stabilized carbanion undergoes an intramolecular Michael addition to the enone, and (3) the resulting enolate displaces phenylsulfinyl moiety from the tricyclooctanone. The amount of HMPA (3 mol equivalents) is critical for effective cyclization of the enolate. 

CYCLOBUTADIENE IN SYNTHESIS endo-TRICYCLO[4.4.0.02 5]DECA-3,8-DIEN-7,IO-DIONE... 

The synthesis of fUido-tricyclo[4.4.0.02 5]deca-3,8-dien-7,10-dione and verification of its endo-configuration has been reported earlier.3 This adduet is a useful starting material for the syntheses of tetracyclo-[5.3.0.02 6.03 10]deca-4,8-diene,s tricyclo[4.4.0.02 5]deca-3,7,9-triene,6 cis, syn, cjs-tricyclo[5.3.0.02,6]deca-4,8-dien-3,10-dione,7 and 4-oxahexa-cyclo[5.4.0.02 6.03 10.05 9.08,11]undecane.a... 

The recent upsurge of interest in systems of theoretical interest demands practical syntheses of several important compounds. These are BICYCLO[2.l.0]PENT-2-ENE, BENZOCYCLOPROPENE, 1,6-OXIDO[10]ANNULENE, and others. ewdo-TRICYCLO[4.4.0.02 5]-DECA-3,8-DIENE-7,10-DIONE is utilized as a model for the use of CYCLOBUTADIENE IN SYNTHESIS, and a stable monomeric ketene, icri-BUTYLCYANOKETENE offers opportunities for further studies of this interesting species. 

Spiroepoxy-endo-tricyclo[5.2.2.026]undeca-4,10-dien-8-one Spiro[4,7-ethano-lH- indene-8,2 -oxiran]-9-one, 3a,4,7,l,7a-tetrahydro- (146924-02-9)... 

Lithium-13-hydrido- 13-bora-tricyclo [7.3.1.04 13]tridecan Alkohol 18... 

Entsprechend wird endo-5-Hydroxy-3-methyl-endo-tricyclo[5.2.1,02 6]decen-(3) (89% d.Th. F 79,4-79,9°) erhalten. 

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