ADAMANTANE, 1-FLUORO

Facial selectivity of 5-substituted adamantan-2-ones (6) was initially studied by Giddings and Hudec [62], followed by intensive studies by le Noble s group [63-66]. Electron-withdrawing substituents such as phenyl (6b), fluoro (6c), hydroxyl and trifluoromethyl groups at the 5 position favored the syn addition... 

POLYHYDROGEN FLUORIDE REAGENT 1-FLUORO-ADAMANTANE. Dichloroalkane synthesis is shown in cis-DI-CHLOROALKANES FROM EPOXIDES cis-1,2-DICHLORO-CYCLOHEXANE. Nitrile functionality can be introduced from a ketone, as in NITRILES FROM KETONES CYCLOHEXANENITRILE, or from a reactive diene, as shown in 2,3-DICYANOBUTADIENE AS A REACTIVE INTERMEDIATE BY in situ GENERATION FROM 1,2-DICYANO CYCLOBUTENE 2,3-DICYANO-1,4,4a,9a -TETRAHYDRO-FLUORENE. 

Hydrocarbons reacting with cesium lluoroxysulfate in acetonitrile at 35 C yield mono- and disubstituted products. Norbornane gives 2-e.Yo-fluoronorbornane (20). while adamantane (21) is converted into the 1-fluoro. 2-fluoro, and 1,3-difluoro products with substitution on the tertiary carbon strongly predominating.20... 

The only direct transformation of a hydroxy group to the corresponding fluoro compound has been described in the case of adamantan-l-ol (l).8... 

Recently Barton et al. (98) reported extremely selective high-yield reactions at —78°C in CFCl3 between fluorine and adamantane and substituted adamantanes. 1-Fluoroadamantane is produced in 84% yield from adamantane, and 3-fluoro-/V-trifluoroacetyl adamantane is produced from /V-trifluoro-acetyladamantane in 83% yield (98). In addition, Barton, Hesse and coworkers reported regioselective reactions of a number of steroids with yields ranging from 25 to 75% (99). Some of the selectivity in the steroids is rather remarkable and is thought to result from electrophyllic reactions that are strongly influenced by polar substituents on the molecules and by solvents (98,99) p. 73. Although the yields are very impressive in these reports, no information is provided on the conversion or the scale. 

Nitrile oxides react with the methyl enol ethers of (Rs)-l -fluoro-alkyl-2-(p-tolylsulfinyl)ethanones to produce (45,5/f,/fs)-4,5-dihydroisoxazoles with high regio-and diastereo-selectivity.87 In the 1,3-dipolar cycloaddition of benzonitrile oxide with adamantane-2-thiones and 2-methyleneadamantanes, the favoured approach is syn, as predicted by the Cieplak s transition-state hyperconjugation model.88 The 1,3-dipolar cycloaddition reaction of acetonitrile oxide with bicyclo[2.2.l]hepta-2,5-diene yields two 1 1 adducts and four of six possible 2 1 adducts.89 Moderate catalytic efficiency, ligand acceleration effect, and concentration effect have been observed in the magnesium ion-mediated 1,3-dipolar cycloadditions of stable mesitonitrile oxide to allylic alcohols.90 The cycloaddition reactions of acryloyl derivatives of the Rebek imide benzoxazole with nitrile oxides are very stereoselective but show reaction rates and regioselectivities comparable to simple achiral models.91. 

While tertiary alcohols, tertiary steroidal alcohols " and many benzylic alcohols - are converted smoothly to the fluorinated products, secondary substrates need more severe reaction conditions and primary alcohols do not give the reaction at all. An Organic Synthesis procedure for the preparation of the reagent and its application to the synthesis of 1-fluoro-adamantane has been published examples of fluorides 1 formed using this procedure are given. ... 

Trichloromethylphosphonyl derivatives may be produced by the reaction of phosphorus trichloride with carbon tetrachloride, catalysed by aluminium chloride, followed by quenching. Thus quenching with water leads to the phosphonyl dichloride (21), while ethanethiol yields the analogous thioate (22). Similar conditions have been applied to the synthesis of the phosphorane (23) from 1-fluoro-adamantane. ... 

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