Reactions of nitrosonium tetrafluoroborate in acetonitrile with organic molecules containing nonbonding electrons. Synthesis of acetamides

Abstract

We have recently found that N02BF4 in acetonitrile will abstract hydrogen from saturated hydrocarbons. Under these relatively mild reaction conditions, the incipient carbenium ion is efficiently trapped by the nitrile solvent, and upon hydrolysis of the resulting nitrilium ion acetamides are produced in good yield.'" The Lewis acid character of the nitronium (NO2+) ion is also manifested in its complexation with the nonbonding (n) electrons of alkyl halides1" and ethers, inducing C-X bond heterolysis which results in acetamide formation (eq l).lC Hydrogen,I /I HO halogen, and alkoxide transfer to the nitronium ion was also observed with CF3C( O)ON02 in trifluoroacetic acid and CH3C(O)ONO2 in acetic acid, affording alkyl trifluoroacetates and alkyl acetates, respectively.ld We now report a comparable series of reactions with NOBF4 as the electrophilic reagent in acetonitrile.The nitrosonium ion, NO+, is a reactive electrophilic species that has been utilized synthetically with alkenes,2 amine^,^ amides,, ~ulfoxides,~ and activated aromatic compounds.6 Nitrosonium salts, with nonnucleophilic ions like NOBF, and NOPF,, can be used to advantage in diazonium ion preparation from aryl or primary amines7 and in the nitrosative decomposition of aliphatic azidesa8 Amides and sulfonamides were found to react with NOBF4 under mild conditions to give the corresponding acids., This versatile electrophilic reagent has been shown to abstract hydride ion from activated benzylic positions,9a -_ _ I -(1) (a) Bach, R. D.; Holubka, J. W.; Badger, R. C.; Rajan, S. J. (2) Beckham, L. J.; Fessler, W. A.; Kise, M. A. Chem. Rev. 1951, 48, 319. Ohno, M.; Naruse, K.; Torimitsu, S.; Teresawa, I. J . Am. Chem. Soc. 1: )66, 88, 3168. (3) Sigel, H.; Brintzinger, H. Helu. Chim. Acta 1965, 48,433. France, H.; Heilbron, I. M.; Hey, D. H.to oxidize benzyl alcohols, and to oxidize trimethylsilyl and tributylstannyl ethers to carbonyl compounds.gb Activated benzyl and benzhydryl esters are also oxidatively cleaved to the parent acid or ketone.gc Alkenes also undergo electrophilic addition by NOBF, in acetonitrile to afford 2-methyl-N-hydroxyimidazolium saltsegd Results and DiscussionTo date there has been no systematic study of the reaction of NOBF, with alkyl halides or ethers in the condensed phase. In the gas phase, ion-molecule reactions of NO+ with organic halidedo closely paralleled our results with both NO+ and NO,+ in s o l~t i o n .~ In the absence of solvent, NO+ exhibits a high electron affinity and will abstract hydrogen from normal, branched, or cyclic hydrocarbons.lOJ1 It was the goal of the present study to provide a comparison between the reactivity of N02BF4 and NOBF4 in acetonitrile and to develop a convenient synthetic procedure for the conversion of alkyl halides and ethers to their respective acetamides.In a typical reaction, the alkyl halide or ether is added to 1 equiv of NOBF, in acetonitrile a t 0 " C and allowed to stir at room temperature; the reaction is then quenched with water. Product isolation is not complicated by th...

Alkyliodines in High Oxidation State: Enhanced Synthetic Possibilities and Accelerated Catalyst Turn‐Over

“…These observations were confirmed by Bach, who employed nitrosonium tetrafluoroborate. [29] This corroborates earlier investigations with nitronium tetrafluoroboratea sactivating agent. [30a] When the correspondingnitronium acetate or trifluoroacetate were used, the acetic or trifluoracetice sters were formed.…”

[1-(1-Adamantylamino)ethylidene]oxonium methanesulfonate

“…For previously published structures of N-(1-adamantyl)acetamide, see: Prö hl et al (1997); Kashino et al (1998); Mizoguchi et al (1997). For the preparation of N-(1adamantyl)acetamide, see: Bach et al (1979Bach et al ( , 1980; Gerzon et al (1963); Stetter et al (1959Stetter et al ( , 1960. For the biological activity of related adamantane derivatives, see: Davies et al (1964); Aldrich et al (1971).…”

Amidation of adamantane and diamantane with acetonitrile and bromotrichloromethane in the presence of Mo(CO)6 in aqueous medium

“…Known methods for the preparation of N-acetyl derivatives of 1-aminoadamantane are based on reactions of 1-X-substituted adamantanes (X = Br, I, OMe, Cl, F, OH, CF 3 COO, O 2 NO) with acetonitrile in the presence of excess catalyst such as NO 2 BF 4 [6], NOPF 6 [7], (CF 3 SO 2 ) 2 O [8], CF 3 COOH, BF 3 · Et 2 O [9], and H 2 SO 4 [10]. Baklan et al [11] synthesized N-(1-adamantyl)acetamide (II) by reaction of adamantane (I) with acetonitrile in bromine as solvent and catalyst and subsequent hydrolysis.…”

“…We performed direct one-pot amidation of adamantane (I) with acetonitrile in the presence of molybdenum hexacarbonyl Mo(CO) 6 and bromotrichloromethane BrCCl 3 in aqueous medium. The reaction ISSN 1070-4280, Russian Journal of Organic Chemistry, 2011, Vol.…”

“…Under analogous conditions, diamantane (IV) was completely converted into a mixture of N-(1-and 4-diamantyl)acetamides V and VI and 1-and 4-bromodiamantanes VII and VIII at a ratio of 2 : 1 : 0.5 : 0.4. The reactant and catalyst ratio Mo(CO)6 -I (or IV)-BrCCl 3 -MeCN-H 2 O was 3 : 100 : 100 : 150 : 200.…”