Noradamantan-2-one

Noradamantanes.—Reaction of noradamantan-2-one oxime (662 synianti = 33 67) with polyphosphate ester afforded products of Beckmann rearrangement and of fragmentation (663)—(667). The products (663) and (665) originate from syn-(622), whereas (664), (666), and (667) arise from anti-(662) product distribution was found to be time-dependent, and (663) and (664) were converted into (665)-(667) under the... 

Noradamantanes.—The synthesis of 2- and 9-noradamantanone has been achieved by an enamine route in which the key intermediate (726) is obtained the imminium function if readily replaced by a selective carbonyl protecting group, and ring closure is then achieved by base-catalysed elimination of the analogous mesylate esters. Homoketonization of 2-acetoxytriaxane (727) in deuteriated media produces[4- H]-noradamantan-2-one (728) with almost complete retention in acid solution and with... 

For a review of the Demjanow and Tiffeneau-Demjanow ring expansions, see ref. [2] [16]. Other references Comparison of diazomethane and Tiffeneau-Demjanow homologation in the steroid field [17] [18], 9-(aminomethyl)noradamantane [19], 2-adamantanone derivatives [20], in bicyclo[3.3.1]nonan-2-one [21]. 

Protoadamantanone is a versatile intermediate for the synthesis of not only protoadamantane derivatives,but also 1,2- and 2,4-disubstituted adamantanes, 2-substituted noradamantanes, and 4(5)-substituted 4-homoprotoadamantanes. 4-Protoadamantanone has been prepared by the nitrous acid deamination of 2-amino-l-adamantanol (77%), by aprotic diazo-tization of endo-7-aminomethylbicyclo[3.3.1]nonan-3-one in benzene with an equivalent amount of acetic acid (67%), and by thermolysis of 1-adamantyl hypohalites followed by base-promoted cyclization of the resulting halo ketones (32-37%).In spite of low and erratic yields, the last reaction sequence has provided the most convenient route to the protoadamantanes, since the other two approaches require lengthy syntheses of the starting materials. 

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