Octan-2-one: and

An excellent method for the conversion of ether-soluble secondary alcohols to the corresponding ketones is by chromic acid oxidation in a two-phase ether-water system. The reaction is carried out at 25-30 °C with the stoichiometric quantity of chromic acid calculated on the basis of the above equation, and is exemplified by the preparation of octan-2-one and cyclohexanone (Expt 5.86). The success of this procedure is evidently due to the rapid formation of the chromate ester of the alcohol, which is then extracted into the aqueous phase, followed by formation of the ketone which is then extracted back into the ether phase and is thus protected from undesirable side reactions. 

Quideau, S., and Ralph, J. (1993) Synthesis of 4,8-bis(4-hydroxy-3-methoxyphenyl)-3, 7,dioxabicyclo[3.3.0]octan-2-ones and determination of their relative configuration via long-range proton couplings. J. Chem. Soc., Perkin Trans. 1 (6), 653-659. 

On heating 4-hydroxycyclo-octanone with dicyclohexylcarbodi-imide, a clean transannular reaction occurs to give bicyclo[5,l,0]octan-2-one the same product is obtained by treating (268 Y = OTs. X = H) with base. The isomer (268 Y = H, X = OTs) can similarly be converted into bicyclo[4,2,0]-octan-2-one, and (269) gives (270) stereospecifically. 

Exclusive exo (equatorial) attack is also observed with bicyclo[3.2.1]octan-3-one (5), whereas addition of methylmagnesium iodide to bicyclo[3.2.1]octan-2-one (7) affords the diastereomeric products in almost equal amounts5i. The cyclohexanone moiety of both bicyclic ketones 5 and 7 adopts a chair conformation and therefore the 3,5-diaxialethano bridge in... 

As a first step in the prepartion of polymers patterned after the repeating unit of nonactin 56, Moore and Kelley53 synthesized 3,8-dioxabicyclo[3.2.1 ]octan-2-one 57 and its corresponding polyester 58. The monomer was prepared from 5-hydroxy-methylpyran-2-carboxylic acid in overall yield of 20%. It was heated with a catalytic amount of tert-butoxytitanate under nitrogen for 3 hr at 100 °C. The temperature... 

Mehta et al. also studied the facial selectivities of 5,6-exo,eji o-disubstituted bicyclo[2.2.2]octan-2-ones 18 [75, 78]. These systems are related to the 2,3-exo,ex( -disubstituted 7-norbomanones 14, but differ in the direction of the carbonyl n face. Hydride reduction of 5,6-exo,ex( -disubstituted bicyclo[2.2.2] octan-2-ones (18) with NaBH and DIBAL-H and methylation with MeLi were smdied [75, 78],... 

Although there is evidence that quaternary ammonium salts are cleaved by sodium borohydride at high temperature [7], initial studies suggested that the quaternary ammonium borohydrides might have some synthetic value in their selectivity, e.g. aldehydes are reduced by an excess of the quaternary ammonium salts under homogeneous conditions in benzene at 25 °C, whereas ketones are recovered unchanged and are only partially reduced at 65 °C [2], The reduction of esters also requires the elevated temperature, whereas nitriles are not reduced even after prolonged reaction at 65 °C. Evidence that the two-phase (benzene water) reduction of octan-2-one by sodium borohydride was some 20-30 times faster in the presence of Aliquat, than in the absence of the catalyst [8], established the potential use of the mote lipophilic catalysts. 

A good example of clearable and non-clearable stereocentres is found in the two following stereoisomers of bicylo[3.3.0]octan-2-one, in which the shape of the molecule forces the attack of the nucleophile to the carbonyl group from the convex face (attack at the (3-face). 

Cis-RuClj(phen)3 is made as black crystals by reaction of RUCI3 with (phen). As CM-RuCl2(phen)3/aq. yO / BuOH or 1,2-dimethoxyethane it stereospecifically epoxidised oleic acid to 9, 10-epoxyoctadecanoic acid [833] The reagent cis-RuCljlphey /aq. Li(C10)/CH3Cl2 oxidised dipropylether to propylpropionate, tet-rahycfiopyran to 6-valerolactone, adamantane to adamantan-l-ol and adamantanone, and octan-2-ol to octan-2-one [834],... 

The system [RuCl(dppp)j]Vaq. Oxone /CHjClj oxidised primary and secondary alcohols to aldehydes and ketones ([Ru(H30) PW (0)3, ] , RuClj and cis-RuCydmso) also catalysed the reaction) [933], while fra i-RuCl2(dppp)2 and [RuCl(ppy)J+/aq. Li(C10)/CH3Cl3, like c/x-RuC phen), oxidised octan-2-ol to octan-2-one [934], As [RuCKdppp) ] or [Rua(ppy)2] /PhlO/CH3Clj they epoxidised nor-bomene, styrene, stilbene, hex-l-ene and franx-hex-2-ene a number of by-products (alcohols, aldehydes and ketones) were also formed. Kinetic measurements and experiments using suggested the intermediacy of [Ru (0)Cl(dppp)J [932, 935],... 

Irradiation of cyclopent-2-enones in the presence of allenes affords mixtures of 6- and 7-methylenebicyclo[3.2.0]heptan-2-ones, the latter regioisomers being formed preferentially.4,5 From cyclohex-2-enones and allene, 8-methylenebicyclo[4.2.0]octan-2-ones are formed regiose-lectively.6 In contrast, six-membered a,/i-unsaturated lactones and allene afford mixtures of regioisomers.7 Mechanistic arguments for the stereochemical outcome of allene photocycloadditions to steroidal enones have been discussed.8... 

BicycIo[4.2.0]octan-2-ones were cleaved by Lewis acids such as aluminum trichloride, boron trifluoride, tin(IV) chloride and zinc(II) acetate in the presence of acetic anhydride to afford enol acetates of cycloocta-l,5-dienols.155... 

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