Bicyclo octanol

Under similar conditions, cyclooctanone gave cyclooctanol and a bicyclo-octanol of unknown structure. 

A series of bicyclo[3.3.0]octanols are accessible by electroreductive tandem cyclization of linear allyl pentenyl ketones 189, as shown by Kariv-Miller et al. [189]. The electrolyses are carried out with an Hg-pool cathode and a Pt-flag anode. As electrolyte, tetrabutylammonium tetrafluororborate is used. The reaction is stereoselective, yielding only two isomers 192 and 193. In a competing reaction, a small amount of the monocyclic alcohol is formed. Since all the monocycles have the 1-allyl and the 2-methyl group in trans geometry it is assumed that this terminates the reaction. The formation of a bicyclic product requires that the first cyclization provides the cis radical anion which leads to cis-ring juncture [190] (Scheme 37). 

The stereospecific syntheses of the 2a- and 2/J-cw-bicyclo[3.3.0]octanols have been described,277 as have stereospecific approaches to 3,7-disubstituted derivatives.278 ... 

Transannulation of the mesylate (33), derived from 4,8-dimethylcycloocta-4-en-l-ol, using sodium carbonate in aqueous dioxane has provided the bicyclo[3.3.0]octanol (34), a central precursor to the monoterpene iridomyrmecin (35 equation 13). In studies of the biomimetic synthesis of the natural tri-quinanes capnellene (37 equation 14) and pentalenene (40 equation IS) Pattenden et al. have shown that both molecules can be produced from appropriate cycloocta-l,S-diene precursors, i.e. (36) and (39) [or indeed their corresponding positional isomers (38) and (41), respectively] by treatment with boron trifluoride. Mehta et al. have described an alternative transannulation approach to the triquinane unit found in pentalenene, i.e. (42) - (43 equation 16), and also to the ring system (44 equation 17) found... 

Transannular cyclization of ketoalkenes was first reported in 1965. Treatment of the conformationally restricted ketone (104) with sodium in moist ether gave the alcohol (105 equation 127). Similarly the ketoalkene (106) transannulated in 73% yield by exposure to sodium in refluxing propanol (equation 128). Conformational restriction is not a prerequisite for transannular reaction thus the caryophyllene (107) undergoes cyclization to the alcohol (108) with lithium in liquid ammonia (equation 129). Transannulation across a nine-membered ring has also been observed upon treatment of ketone (109 equation 130) with samarium diiodide, via cyclization of the ketoalkene (110). Of more practical importance, the electrochemical transannulation of the cyclooct-4-en-l-one gives the bicyclo[3.3.0]octanol (111 equation 131). ... 

In fact, whenever the primary carbonium ion is formed from the proper substrate, ring expansion is observed this is the case in the acid-catalyzed dehydration of 2-hydroxymethylbicyclo[2.2.1]heptane (23), producing a mixture of 2.5% methylenebicyclo[2.2.1]heptane (7), 87% bicyclo[3.2.1]-2-octene (5), and 10% bicyclo[3.3.0]-2-octene (6) and in the nitrous acid deamination of 2-aminomethylbicyclo[2.2.1]-heptane to bicyclo[3.2.1]- and bicyclo[2.2.2]octanols 30). 

The passage from bicyclo[2.2.2]octane structures to the isomeric bicyclo[3.2.1]octanes is irreversible for all practical purposes in the CsHiz and C9H14 series (it was not investigated in the CioHie series) and this conclusion is substantiated by other facts the acid-catalyzed dehydration of 2-methylbicyclo[3.2.1]-2-octanols and 3-methylbicyclo-[3.2.1]-3-octanols gives small quantities of methylbicyclo[2.2.2]octenes 30), while the acid-catalyzed hydration of bicyclo[2.2.2]-2-octene forms the bicyclo[3.2.1]-2-octanol 27) the nitrous acid deamination of 2-aminobicyclo[2.2.2]-5-octene goes to bicyclo[3.2.1]octenols 31) and the solvolysis of bicyclo[2.2.2]-5-octen-2-ol esters to bicyclo[3.2.1]octenols 32). 

On the other hand, carbonylation via a one-electron reduction system by reducing metals can also lead to useful transformations [Scheme 4-33]. The first example in Scheme 4-34 shows that a zinc reduction system of pent-4-enyl iodide undergoes dual annulations, a [4-f1] radical annulation with CO and a [3-f2] anion annulation with alkenes, to give a bicyclo[3.3.0]octanol, in which four C-C bonds are produced [59]. An extension of the present strategy to the construction of bicyclo[3.2.1]octanol skeletons has also been successful with a system in which 6-endo cyclization is favored over 5-exo cyclization. In these two reactions three C-C bonds were created by radical reactions and one by anionic reaction. 

Bicyclooctyl Cations. Solvolyses of endo-2-bicyclo[3.2.1]octyl tosylate (73)55S and 4-cycloheptenylcarbinyl brosylate (4< 7)377 555 give similar product mixtures consisting primarily of endo-2-bicyclo [3.2.1] octanol or its acetate (819)... 

Among the many other cyclic secondary alcohols that have been obtained by lipase-catalyzed enantiomer-selective acylation with high enantiomeric excess are aminofunctionalized cycloalkanols (40, 45-62, 75), bicyclo[3.3.0]octanols (78, 84-86), different types of tri- and tetracyclic alcohols (96-104), substituted indanols (87-94,123), hydroxy lactams (106,109-112) and brominated cyclohexenol derivatives (74, 77,124-127) (Table 11.1-21). 

The reductive coupling of bis(enones) is another reaction class that may involve alkene-derived metallacyclopentanes. Treatment of a symmetrical bis(enone) 89 tvith bis(r] -cy-cloocta-l,5-diene)nickel(0) (2) and butyllithium/zinc(II) chloride leads to coupling of the two enone -carbons followed by an intramolecular aldol addition to afford bicyclo[3.3.0]-octanols 90 (Scheme Sterically hindered enones have also been shovm to partic-... 

To find the structure-activity relationships in this series esters of both non-substituted 3-hydroxyquinuclidine and 3-hydroxyquinuclidines having various substituents in the 3-, 6- and other positions have been synthesized. Esters of homologous aminoalcohols 3-hydroxymethyl- and 3-(j8-hydroxyethyl)-qui-nuchdines, esters of isomeric and homologous 1-azabicycloalkanols - 1-aza-bicyclo(3,2,l)-octanol-6 and l-azabicyclo(3,3,2)-nonanole-4 and also esters containing the opened 3-hydroxy-quinuclidine structure, e.g. AT-alkyl-3-hy-... 

Isolauronolalkohol-acetat 6, 51. Bioyolo-[1.3.3].nonanol-(2)-acetat 6 II64. 2-Metbyl.bicyclo.[1.2.3].octanol-(4).acetat 6. 51. 

Kinetic data obtained in the pyrolyses of endo- and exo-5-methylbicyclo[2,2,2]oct-2-ene suggests that biradical mechanisms are involved. The conformations of bicyclo[2,2,2]octane derivatives have been examined by the classic extended Hiickel theory the existence of privileged conformations is discussed. It has been found that aminobicyclo [2,2,2] octanols are quaternized faster than are the corresponding amino-bornanols, probably because the relative flexibility of the bicyclo-octanes allows for easier accommodation of the cation. The effects of H-bonding, steric and electronic features on the pX values of these amino-alcohols is discussed. 

Methanesulfonyl chloride added at 0° to l-methyl-l-(2-hydroxyethyl)-1,2-di-hydronaphthalene and dry pyridine, stirred 18 hrs. at room temp., the soln. of the resulting crude mesylate in wet benzene-petroleum ether chromatographed over basic alumina, and eluted with ether exo-l-methyl-2,3-benzo-bicyclo [3.2.1]-4-octanol. Y 54%.—This is a remarkably facile ring closure through double bond participation. W. Herz and G. Gaple, Am. Soc. 84, 3517 (1962). 

It has been reported that, while ring expansion by ionic fragmentation of a bicyclo[3.3.0]octanol could not be achieved, an alkoxyl radical generated from the octanol resulted in a selective P-cleavage of the fused bond to give a functionalized bridged cyclooctane derivative (Scheme 69). 

As for other bicyclic compounds, the resolution of a few bicyclo[3.3.0]octanols [234,235] proceeds with high stereoselectivity. By an efficient enzymatic process, a similar bicyclic structure can be obtained optically pure as a chiral intermediate for the synthesis of [Pg.441]

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