Bicyclo decane from

A synthesis of the highly functionalized tricyclic core of guanacasterpene represents an example of the Rh(i)-catalyzed intramolecular PKR leading to bicyclo[5,3,0]-decanes from the allenynes (Equation (50)). ... 

The intermediacy of a carbene has also been proposed to explain the formation of bicydo[5.3.0]decane and bicyclo[4.4.0]decane from irradiation of the cis and trans isomers of cyclodecene (Figure 237)P ... 

Bicyclo[4.3.1]decane from bicyclo[4.2.2]decane ring... 

Intramolecular cyclopropanation of 4-aryl-1 -diazo-2-butanones 240 allows construction of the bicyclo[5.3.0]decane framework 12). In a reaction sequence analogous to that described above for the intermolecular ketocarbenoid reaction, bicyclo-[5.3.0]deca-l,3,5-trien-8-ones 241 are formed. They rearrange to the conjugated isomers 242 at the high temperatures needed if the reaction is catalyzed by copper 2311 or CuCl 232), but can be isolated in excellent yield from the Rh2(OAc)4-promoted reaction which occurs at lower temperature 233... 

In another approach 145, dibromocarbene was added to ( + )-cyclononadiene 127 to give (after reduction of the outside adduct) ( + )-trans-bicyclo[7.1.0]decane 132). From the dextrorotatory enantiomer of the above-mentioned dibromo-derivative 128, ( + )-trans-bicyclo[6,1.0]nonane 129) was accessible. Comparison of the chiroptical properties of (+)-129 and (+)-132 led to the conclusion that 127 had the (+)(/ )(axial) chirality145) in agreement with the results reported above 144). 

Figures 16.8.2(h), (i), and (j) show the structures of Se2J, Se2+, and Se, respectively. They all consist of seven- or eight-membered rings connected by short chains. Each homopolyatomic cation has two three-coordinate atoms that formally carry the positive charges. Se2g has a bicyclo[2.2.4]decane geometry. The Se-Se bond distances vary between 225 and 240 pm, and the Se-Se-Se angles range from 97° to 106°. Se2+ and Se2+ comprise a pair of seven-membered rings connected by a three- and four-atom chain, respectively.

In summary, intramolecular reactions of a considerable variety of diones provide interesting mechanistic questions as well as a route forj construction of four- and five-membered rings in high photochemical and chemical yields. Except for a synthesis of cis- and trans-bicyclo[7.1.0]decan-2-one from cyclodecane-1,2-dione 122), this potential has been ignored. 

Curci et al. subjected cyclodecyne 125 to epoxidation with methyl(trifluoromethyl)dioxirane and observed a mixture (7 1) of m-bicyclo[5.3.0]decan-2-one 126 and m-bicyclo[4.4.0]decan-2-one 127, these products presumably arising via respective 1,5- and 1,6-transannular insertion pathways into the intermediate oxirene (Scheme 62) <1992TL7929, 1996CHEC-II(1)145>. Prior to this report, Concannon and Ciabattoni had observed the product profiles arising from the oxidation of several cycloalkynes with MCPBA (Table 18) <1973JA3284>. 

Stereoselective, fused-ring alicyclic alcohols are prepared in 10-77% yields from haloalkylalicyclic ketones. The cyclic ketones range from C5 to C7, with iodo-, bromopropyl-, or bromobutyl-substitution in the 2-position. Bicyclo[3.3.0]octan-l-ols, [4.3.0]nona-l-ols, [4.4.0]deca-l-ols, and [5.3.0]decan-l-ols are also prepared. When the side chain is extended to iodopentyl, no bicyclic products are obtained. Usually the ring fusion is cisoid [53],... 

J.K. Cha et al. developed a stereocontrolled synthesis of bicyclo[5.3.0]decan-3-ones from readily available acyclic substrates. Acyclic olefin-tethered amides were first subjected to the intramolecular Kulinkovich reaction to prepare bicyclic aminocyclopropanes. This was followed by a tandem ring-expansion-cyclization sequence triggered by aerobic oxidation. The reactive intermediates in this tandem process were aminium radicals (radical cations). The p-anisidine group was chosen to lower the amine oxidation potential. This substituent was crucial for the generation of the aminium radical (if Ar = phenyl, the ring aerobic oxidation is not feasible). 

From our results at the higher temperature used (250°) and larger contact times (Figs. 7 and 10), the bicyclo[4.3.0]octane or perhydrindane structures seem to appear almost simultaneously and in constant ratios. Their thermodynamic stabilities must be rather close. Finally, and for the sake of completeness, the bicyclo[4.4.0]decane structure was added to the general scheme of Fig. 13, in spite of the fact that octalins have not yet been isolated from our CioHie isomerization mixtures. 

An alternative method whereby a fused-ring oxirene may be generated is the epoxidation of a cycloalkyne. Curci et al. have employed methyl(trifluoromethyl)dioxirane (TFD) toward that end, and obtained (215) and c -bicyclo[4.4.0]decan-2-one in ca. 7 1 ratio from cyclodecayne (213) <92TL7929>. These products obviously stem from stereoselective 1,5- and 1,6-transannular insertion pathways. The authors conclude that the products of cycloalkyne oxidations may arise directly from trapping of the oxirene intermediates by transannular hydrogen transfer, as shown in Scheme 46. 

Interestingly, when substituted norbornenes, such as dimethyl bicyclo[2.2.1]hept-2-ene-2,3-dicarboxylate (23), are employed in a nickel-catalyzed reaction, the only reaction product is dimethyl cxn-4-methylenetricyclo[5.2.1.0 ]decane-2,6-dicarboxylate (24), arising from an unusually selective, formal distal ring cleavage of the MCP. ... 

A solution of 217 mg (0.654 mmol) of lxhydroxy-2a,6/i,8j8-trimethyl-10-oxo-7j8-[2-(3-tetrahydro-furanyl)ethyl]-r/ m-bicyclo[4.4.0]decane-2/t-carboxylicacid (dehydrotctrahvdromarrubic acid) in 15 mL of methanol is added with stirring to 300 niL of liquid ammonia. 800 mg of lithium metal are added in portions over a period of 30 min, waiting after each addition until the blue color has disappeared before the addition of more of the metal. When all the lithium has been added, 15 g of ammonium chloride arc slowly added to the mixture, which is left stirring until all the ammonia has evaporated. Ice water is added to the residue and the solution is acidified with hydrochloric acid. The acidified solution is extracted with ethyl acetate, and the combined ethyl acetate fractions arc washed with sat. aq sodium chloride and dried over Nu,S04. Evaporation gives the crude product [yield 211 mg (96%)] which is recrystallizcd from ethyl acetate yield 162 mg (74%) mp 179 — 184"C mixed mp 179-181 C. 

Aqueous solutions of sodium nitrite (4.5) and of acetic acid (4 g) are added successively to one of bicyclo[3.2.2]nonane-6-methylamine hydrochloride (13 g) in water (50 ml) while a rapid stream of steam is passed through the solution. When this reaction ceases, further sodium nitrite (2 g) and acetic acid (1.8 g) are added and distillation is continued. The distillate is extracted with ether, and the extracts are washed with dilute hydrochloric acid until free from amine, neutralized with sodium hydrogen carbonate, and evaporated. The residue is mixed with 10% sodium hydroxide solution (10 ml) and distilled in steam. The bicyclo-[3.3.2]decan-3-ol that solidifies in the distillate is collected (7.5 g, 71 %). 

A synthetically useful example of this process is the conversion of 117 to 120, which involves a 1,2-alkyl shift, and was part of Hwu s synthesis of (-)-solavetivone. 38 jhe alkyl fragment is actually part of the bicyclic ling system, one arm of the bicyclo[4.4.0]decane ring system. Reaction of the OH unit with the Lewis acid resulted in formation of the tertiary cation 118, which was followed by a 1,2-alkyls shift to give 119, where the new cation is stabilized by the adjacent silicon of the trimethylsilyl group. 39 Loss of the trimethylsilyl group from 119 gives spiran (120). 

Deprotonation of the dication cij-1,6-dimethyl-l,6-diazoniabicyclo[4.4.0]decane (66) results in products derived from deprotonation at a methyl group, including 1-methyl-l-azonia-6-bicyclo[4.4.1]undecane (67) <84JCS(P2)4ll, 86J0C3169>, and deprotonation of the dication of 6-methyl-l,6-diazoniatricyclo[6.2.2.0 ]dodecane (68) affords the monoion of 1-methyl-l-azonia-6-aza-tricyclo[7.2.1.0 "]dodecane (69) <86JOC3i69>. 

Three modified clerodanes 9, 10 and 11 were extracted from Dodonaea viscosa. These compounds have been proposed as hypothetical intermediates in the biosynthesis of diterpenes containing bicyclo[5.4.0]undecane or bicyclo[5.3.0]decane ring systems <01T2981>. Three furoclerodanes, namely 12-epi-Teukotschyn, teughrebin and 12-epi-... 

A recent report shows the preparation of a bicyclo[5.3.0]decane in high yield from a cyclodecyne (Eq. 14), a reaction which putatively proceeds via a carbene intermediate. 

The development of blue colours in certain essential oils, e.g. oil of camomile, after such simple operations as distillation, steam distillation or treatment with acids or oxidising agents, has been noted at various times since the fifteenth century. Many such oils contain hydrogenated azulene derivatives (f,e. derivatives of bicyclo[5.3.0]decane) in their higher boiling fractions and the development of blue colours stems from dehydrogenation of these compounds. For example, an intensely blue coloured fraction, b.p. 

A novel properly of an electronically excited molecule can be chirality that exists only because of photoexcitation. Miesen, F. W. A. M. Wollersheim, A. P. P. Meskers, S. C. J. Dekkers, H. P. J. M- Meijer, E. W. /. Am. Chem. Soc. 1994,116,5129 reported the synthesis of optically pure 3-( n,Ji )-(lS,6R)-bicyclo[4.4.0]decane-3,8-dione, which is chiral only in the excited state. The chirality was detected in the circular polarization of chemiluminescence associated with its synthesis from an optically active 1,2-dioxetane precursor. 

The thermal reaction, at room temperature, of A -bicyclo[2A0]hexene (277) gave, besides polymeric material, a dimer now identified as 2,5-dimethylenetricyclo-[4,2,2,0 ]decane (278). Reaction of (277) with irons, frans-dimethyl-2,5-hexadiene gave the olefin (279) and reduction of both (278) and (279) gave cis-2,5-dimethyltri-cyclo[4,2,2,0 ]decane. The reactive double bond in (277) differs from that usually associated with thermal olefin dimerizations. In most cases, such reactivity has been associated with double bonds which are torsionally strained. In (277) the torsion angle about the double bond must be zero and the reactivity must be associated with angular deformation at the olefinic carbons. Addition of ketene to (277) gave 3-methyl-6-methylenecyclohex-2-ene-l-one. In both reaction with ketene and dimerization, [2,2,2]propellanes would appear to be reasonable intermediates. 

Cyclized products are obtained from the vapour-phase fluorination of cycloalkanes using cobalt(iii) fluoride, e.g., cyclo-octane gives a mixture of eight fluorocarbons including perfluorobicyclo[3,3,0]octane and cyclodecane gives a complex mixture including perfluoro-cis- and -tra s-bicyclo[4,4,0]decanes. ... 

Cyclopentanone annelation via thermolysis of trimethylsilyl enol ethers of cyclopropyl methyl ketones has been studied a good yield of bicyclo[5,3,0]decan-8-one was obtained from (321 R = Q=CH2)OSiMe3 R = H), but only a low yield of bicyclo[5,3,0]decan-9-one was obtained from [321 R = H, R = C(=CH2)-... 

---