Sur la réduction par NaBH<sub>4</sub> de quelques nitriles α, β-insaturés

Pépin, Yvon; Nazémi, Hassan; Payette, Daniel R.

doi:10.1139/v78-008

Cited by 7 publications

(1 citation statement)

References 14 publications

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“…The latter product arises from a 1,2 hydride shift to the developing adjacent positive center (eq 2). 12 The selective reaction of only one functional IJ H cti3 group in 1,4-diiodobutane afforded (4-iodobuty1)acetamide. The absence of rearranged product is most likely a result of neighboring-group participation by iodine (eq 3).…”

Section: Resultsmentioning

confidence: 99%

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

Bach¹,

Taaffee²,

Rajan³

1980

J. Org. Chem.

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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...

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Section: Resultsmentioning

confidence: 99%

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

Bach¹,

Taaffee²,

Rajan³

1980

J. Org. Chem.

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Formation of Alkanes and Arenes by Reduction

Larock

Zhang

2017

Comprehensive Organic Transformations

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Cyclic Alkanes Arenes Alkenes Alkynes Organic Halides Amines and Derivatives Nitro Compounds Ethers Alcohols and Phenols Sulfur Compounds Selenium and Tellurium Compounds Aldehydes and Ketones Acetals Carboxylic Acids Acid Halides Anhydrides Esters and Lactones Nitriles Isonitriles

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A new procedure for regioselective synthesis of 8,9‐dichloro‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepine (LY134046) and its 3‐methyl analogue as inhibitors of phenylethanolamine N‐methyltransferase (PNMT)

Grunewald

Paradkar

Stillions

et al. 1991

Journal of Heterocyclic Chem

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A regioselective synthesis of 8,9‐dichloro‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepine (LY134046, 10) and its 3‐methyl analogue 26 from 6,7‐dichloro‐3‐hydroxyphthalide (16) is described. The key step involved 1,4‐hydride addition to the α,β‐unsaturated nitrile 17 to give the saturated nitrile 18 using sodium borohydride in 2‐propanol. In the preparation of LY134046 10, the COOH group in 18 was first esterified and then the nitrile function was selectively reduced with borane to yield the aminoester 20. The aminoester 20 was then cyclized to the azepinone 21 which on reduction with borane provided LY134046 10 in an overall yield of 22%. The route is adaptable to the preparation of hitherto unknown 3‐substituted‐2‐benzazepines as demonstrated by the preparation of the 3‐methyl analogue 26. In this case the nitrile 18 was reacted with an excess methylmagnesium iodide to give the ketoacid 22. Esterification of 22 followed by reductive amination with sodium cyanoborohydride and ammonium acetate provided the aminoester 24, which was then converted to the target benzazepine 26 as described earlier for the title compound. The reaction conditions and the reagents used throughout the sequence are fairly mild and many functional groups may be tolerated. The only limitation to this procedure is the availability of the corresponding hydroxyphthalide. A variation in the choice of reagent in the Grignard reaction of 18 should provide an access to a variety of 3‐substituted‐2‐benzazepines.

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Sur la réduction par NaBH₄ de quelques nitriles α, β-insaturés

Cited by 7 publications

References 14 publications

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

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

Formation of Alkanes and Arenes by Reduction

A new procedure for regioselective synthesis of 8,9‐dichloro‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepine (LY134046) and its 3‐methyl analogue as inhibitors of phenylethanolamine N‐methyltransferase (PNMT)

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Sur la réduction par NaBH4 de quelques nitriles α, β-insaturés

Cited by 7 publications

References 14 publications

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

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

Formation of Alkanes and Arenes by Reduction

A new procedure for regioselective synthesis of 8,9‐dichloro‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepine (LY134046) and its 3‐methyl analogue as inhibitors of phenylethanolamine N‐methyltransferase (PNMT)

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Sur la réduction par NaBH₄ de quelques nitriles α, β-insaturés