Bicyclo nonane ring system

Kuroda, C.. Sumiya, II.. Murase, A., and Koito, A., Iron(ni)-induced tandem Nazarov cyclization-rearrangement of a-(triincLhylsilylmethyl)divinyl ketone. Synthesis of the bicyclo[4.3.0]nonane ring system via spiro[4.4]nonanc, J. Chem. Soc., Chem. Commun.. 1177. 1997. 

Manzamenone J (66) had the same composition as manzamenone D (61) with a conjugated dienone (Xmax 317 nm) functionality. Analysis of several types of 2D NMR spectra of 66 led to a bicyclo[4.3.0]nonane ring system involving a l(6),2-dien-7-one chromophore. The stereochemistry of the vicinal methine protons on C-8 and C-9 were suggested to be anti from the NOESY spectrum of 66 showing substantial correlations from H-8 to H2-26 and H2-27. The stereochemistry of C-5 position relative to C-8 and C-9 portion remained unassigned. 

Nagaoka, H., Shibuya, K., and Yamada, Y. (1994) Total synthesis of upial, a marine sesquiterpene possessing bicyclo[3.3.1]nonane ring system. Tetrahedron, 50, 661-688. 

Various bicyclic and polycyclic compounds are produced by intramolecular reactions] 127]. In the syntheses of the decalin systems 157 [38] and 158 [128], cis ring Junctions are selectively generated. In the formation of 158, allyhc silyl ether remains intact. A bridged bicyclo[3.3. l]nonane ring 159 was constructed... 

Over 120 references to this heterocyclic ring system has appeared since Mosby1 reviewed the literature and found 28 references prior to 1957. The octahydro derivatives, in addition to being called 1,4-diaza-bicyclo 4.3.0)nonanes or 1,2-trimethylenepiperazines, are also known as anhydrides or lactams of proline with a second amino acid or as diketo-piperazines. The disproportionately large number of octahydro derivatives of this ring system will be treated separately in Section IV,D. 

The most common polyprenylated benzophenones have a bicyclo[3.3. l]nonane B/C-ring system. Approximately 38 bicyclo[3.3.1]nonane benzophenones have been isolated. A typical bicyclo[3.3.1]nonane benzophenone is xanthochymol (138), which is discussed in detail below. 

Another type of carbopalladation is observed in the oxidation of the 2,2-disubstituted alkene attached to the cyclobutanol 104. The shift of the carbon-carbon bond as shown by 105 and ring expansion generate 106. Intramolecular alkene insertion gives the bicyclo[4.3.0]nonane system 107. Finally, 108 is obtained [78],... 

In the case of McycKc systems (133—140) there are not yet enough data available for a detailed discussion to be given. The barriers obtained for the bicyclo [2.2.2]octane (133, 134) and the bicyclo[3.3.1]nonane (139, 140) compounds are in the range expected for the corresponding mono-cyclic systems. In the case of the bicyclo[3.2.2]nonane derivatives 135 and 136 the inversion barriers are larger than in the seven-membered ring compounds 127 and 128. 

Similar results of metal-mediated cyclopropane ring opening have been obtained with saturated polycyclic hydrocarbons containing cyclopropane subunits. Prominent examples are bicyclopropyl (I) and similar systems such as quadricyclane (2 tetracyclo[3.2.0.0 . 0 ]-heptane), tetracyclo[3.3.I.0. 0 ]nonane (3), bicyclo[1.1.0]butane (4) and other bicyclo[n.l.O]alkanes 5, spiropentane (6) and other spirocyclopropanecycloalkanes 7. ... 

An interesting example of a reaction involving conformational equilibria in 3,7,9-substituted bicyclo[3.3.1]nonane systems is the base-induced rearrangement of endo-7,7-dimethylbicyclo[3.3.1]nonan-3-ol-9-one (80) into 81. The rearrangement is rationalized by a reversible intramolecular transfer of hydride from the carbinol methine to the carbonyl carbon (60). The reacting centers at C-3 and C-9 are only placed in proximity when the cyclohexanol ring adopts a boat conformation. The resulting ketol 81 is 2.7 kcal mol 1 more stable than its isomer 80 (60). 

A 5-exo reaction can be observed when ,/Tepoxycyclohexenone is treated with tin(lV) chloride. After a regioselective oxirane ring opening, cyclization follows via axial attack of the alkyne group. The terminal vinyl cation is trapped by chloride and the bicyclo[4 3.0]nonan-2-one system 1 is formed stereoselectively in 94% yield5. 

The bicyclo[3.3.1]nonane system found in rings B and D of lycopodine has been used by two groups in efforts to arrive at the lycopodine system. In the work of Colvin et al. (55) the readily available bicyclo-... 

When the target bicycle lacks a suitably placed double bond in a six-membered ring, retrosynthesis starts with FGA (= add double bond) [95, 96, 97, 98]. In bicyclization reactions forming an endoendo bond, the stereochemistry of the reaction has to be monitored (formation of a cis or of a trans fusion of the two rings). With anellated systems of a five- to a six-membered ring the cis juncture is thermodynamically favored. This renders it possible to reach a cis fused bicyclo[4.3.0]nonane system by an epimerization process following the bicyclization reaction [99] (Scheme 6.25). 

Both the cis- and trans-fused compounds represent valuable models for other, cyclohexane-based systems. Stereochemistry in the cis compounds is specified simply as exo and endo, while the orientations of groups in the trans series and those with a bridgehead double bond are specified based on their orientation as axial (A) or equatorial (E) substituents. Note that this system is distinct from that used with the trans-fused bicyclo[4.3.0]nonanes but it was felt that this inconsistency would be more than repaid here by the ease with which the spatial orientation of the groups could be visualized. Corresponding use of axial and equatorial for the [4.3.0]nonanes would have required new definitions of orientations of substituents on the five-membered ring. 

The diol derivatives of bicyclo[3.3.1]nonanes (Figure 9) are such systems, and the unique molecular shape of this building block has been used to form self-assembled supramolecular structures and inclusion complexes with various guest molecules. Some derivatives of this ring skeleton, the so-called tubuland diols, give controllable crystal structures with a variety of inclusion guests. 

Hyperflorin, an antibiotic isolated from St. John s wort Hypericum perforatum L.), has been found on the basis of chemical and spectroscopic evidence to possess structure (639). ° A review on the conformational analysis of bicyclo[3,3,l]nonanes has appeared,and the conformations of l,5-disubstituted-3,7-dimethyIenebicyclo-[3,3,l]nonane derivatives have been shown, on the basis of lanthanide-induced n.m.r. shifts, to be predominantly in the double-chair form. In a notable paper that contains a wealth of information pertinent to adamantane synthesis, it has been reported that bicyclo[3,3,l]nonane-3,7-dicarboxylic acid, its dimethyl ester, and various derivatives exist mainly in the chair-boat conformation. The synthetic entry to these systems is illustrated for the above diester (643) in which the starting point is adamantanone (640) thus, ring expansion with diazomethane followed by SeOj oxidation gave the a-diketone (641) which was cleaved with periodate to give the diacid (642). Esterification using diazomethane gave (643) which exists, as does the diacid, as... 

The intermediates in the production of (140) were isolated when the formation of ring A was carried out under mild conditions (without boiling with sodium methoxide) which led through the diketone (139) to the epim-eric ketols (141). Rings A and B of these compounds form a bicyclo-[3,3,1]-nonane system [57] originally, these products were assigned the structure of compounds (142) epimeric at C5 with the decalin system of rings A and B [56]. The ratio of the isomers of ketol (141) formed depends on the reaction conditions and, in the first place, on the concentra-... 

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