Friedel-Crafts acylation with N-(trifluoroacetyl)-.alpha.-amino acid chlorides. Application to the preparation of .beta.-arylalkylamines and 3-substituted 1,2,3,4-tetrahydroisoquinolines

Nordlander, J. Eric; Payne, Matthew; Njoroge, F. George; BALK, M. A.; LAIKOS, G. D.; Vishwanath, V. M.

doi:10.1021/jo00196a001

Cited by 53 publications

(33 citation statements)

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“…Chiral N -protected α-amino aryl-ketone are usually used as a precursor in the synthesis of various biologically active compounds [ 1 , 2 ]. The most favorable strategy to synthesize α-amino aryl-ketone is by Friedel–Crafts acylation [ 3 , 4 ] of arenes, which is known as a reliable method that results in satisfactory product yields [ 5 ] and can utilize convenient optically pure α-amino acid derivatives as skeletons [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…The most favorable strategy to synthesize α-amino aryl-ketone is by Friedel–Crafts acylation [ 3 , 4 ] of arenes, which is known as a reliable method that results in satisfactory product yields [ 5 ] and can utilize convenient optically pure α-amino acid derivatives as skeletons [ 6 ]. The α-amino acid chloride [ 1 , 2 , 7 , 8 ] is widely used as an acyl donor to undergo Friedel–Crafts acylation due to its reactivity. However, this acyl donor is unstable, sensitive to moisture and difficult to handle [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Chiral TFA-Protected α-Amino Aryl-Ketone Derivatives with Friedel–Crafts Acylation of α-Amino Acid N-Hydroxysuccinimide Ester

et al. 2017

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Chiral N-protected α-amino aryl-ketones are one of the useful precursors used in the synthesis of various biologically active compounds and can be constructed via Friedel–Crafts acylation of N-protected α-amino acids. One of the drawbacks of this reaction is the utilization of toxic, corrosive and moisture-sensitive acylating reagents. In peptide construction via amide bond formation, N-hydroxysuccinimide ester (OSu), which has high storage stability, can react rapidly with amino components and produces fewer side reactions, including racemization. This study reports the first synthesis and utilization of N-trifluoroacetyl (TFA)-protected α-amino acid-OSu as a potential acyl donor for Friedel–Crafts acylation into various arenes. The TFA-protected isoleucine derivative and its diastereomer TFA-protected allo-isoleucine derivative were investigated to check the retention of α-proton chirality in the Friedel–Crafts reaction. Further utilization of OSu in other branched-chain and unbranched-chain amino acids results in an adequate yield of TFA-protected α-amino aryl-ketone without loss of optical purity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of Chiral TFA-Protected α-Amino Aryl-Ketone Derivatives with Friedel–Crafts Acylation of α-Amino Acid N-Hydroxysuccinimide Ester

et al. 2017

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“…The corresponding acid chlorides of N-trifluoroacylated a-amino acids were prepared in the following pathway by interaction with thionyl chloride (Scheme 2) using several modifications of the conditions described in Ref. [45,46]. The best yields of acid chlorides 7a-7d were achieved with 1.1-fold excess of freshly distilled SOCl 2 as required by stoichiometry, considering that the extra equivalent of thionyl decreased the yield on the following reaction stage.…”

Section: Resultsmentioning

confidence: 99%

Cyclic α-amino acids as precursors for synthesis of 2-amino-3-hetarylpyrrolin-4-ones and their spiro derivatives

et al. 2012

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a-Aminoisobutanoic acid and some representatives of cyclic a-amino acids were converted to corresponding 1-phthalimido-and N-trifluoroacylated acid chlorides. Treatment of 2-(1H-benzimidazol-2-yl)acetonitrile with 1-phthalimidoacid chlorides in DMF unexpectedly gaveOn the other hand, the reaction of hetarylacetonitriles with N-trifluoroacylated acid chlorides gave the desired (3-cyano-2-oxo-3-hetarylpropyl)-2,2,2-trifluoroacetamides that upon detrifluoroacetylation provided the target 2-amino-3-hetarylpyrrolin-4-ones. The acylation of benzoimidazolylaminopyrrolinones by benzoyl chloride leads to formation of 3-benzoyl-2,3-dihydro-5-phenyl-1H-benzo [4,5]imidazo [1,2-c] pyrrolo[3,2-e]pyrimidin-1-ones.

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“…After investigating several conditions, 2 mol % of Pd(OAc) 2 and 4 mol % of RuPhos (Table 5, entry 4) showed the best catalytic performance, affording the product in 71% yield.…”

mentioning

confidence: 99%

“…This coupling is particularly relevant because it provides an easy and efficient alternative to prepare phenethylamines containing free amino groups after appropriate deprotection of the respective Boc and Cbz protecting groups. (2) In summary, we have been described an efficient and convenient synthesis of an important class of compounds through the Suzuki-Miyaura cross-coupling reaction. The potassium β-aminoethyltrifluoroborates, readily obtained as stable crystalline solids in moderate to excellent yields via Snieckus hydroboration with i-PP 2 BH, have successfully proven their utility and versatility as useful aminoethylating reagents in the synthesis of a series of phenethylamines.…”

mentioning

confidence: 99%

β-Aminoethyltrifluoroborates: Efficient Aminoethylations via Suzuki−Miyaura Cross-Coupling

Molander

Vargas

2006

Org. Lett.

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A set of phenethylamines has been successfully prepared via Suzuki-Miyaura cross-coupling of diverse potassium β-aminoethyltrifluoroborates with aryl halides. The potassium β-aminoethyltrifluoroborates were easily prepared via hydroboration of enamine and enamide precursors.Phenethylamines and their structural analogues comprise important substructures of a variety of biologically important compounds including dopamine, tyrosine, amphetamine, and adrenaline. These privileged scaffolds are also widely found as components of alkaloid natural products 1 and often serve as key building blocks in the synthesis of numerous nitrogencontaining complex molecules. Previous methods to introduce an aminoethyl group into an arene have employed the Friedel-Crafts acylation of activated arenes with N-protected amino acid chlorides, 2 Heck arylation of N-vinyloxazolone followed by hydrogenation, 3 and crosscoupling reactions involving β-amino organozinc reagents, which are somewhat unstable to β-elimination. 4 Earlier investigations to access these important units also include the direct coupling of β-aminoethyl organolithiums with aryl-and alkenyl halides. 5 A more broadly applicable Suzuki cross-coupling 6 approach to this interesting class of compounds has been developed by Overman. 7 However, although there are distinct advantages of this one-pot β-aminoethylation procedure in cross-coupling reactions and total synthesis (e.g., the reactions can be performed at room temperature), 8 there are some limitations as well. In particular, the organoborane reagents prepared in situ via hydroboration of benzyl vinyl carbamate cannot be easily isolated and stored, but must be prepared and utilized on a reaction-by-reaction basis.By contrast, potassium organotrifluoroborates have been shown to overcome this particular limitation. These salts are unique organoboron compounds, notable for their stability to moisture and air. 9 They are powders or crystalline solids that are easy to access and handle, and these properties have made them attractive synthetic intermediates. Herein we describe our initial efforts to develop a convenient and practical access to phenethylamines via Suzuki cross-coupling of potassium β-aminoethyltrifluoroborates with aryl electrophiles.To initiate studies on the aminoethylation reactions, a hydroboration protocol was employed that mimicked procedures reported by Overman. 8 Thus, the respective N-vinyl substrates 10 were hydroborated using Snieckus' di(isopropylprenyl)borane (i-PP 2 BH), 11 and the resulting organoborane intermediates were treated with an aqueous solution of KHF 2 to afford the desired β-aminoethyltrifluoroborates 1a-e as depicted in Table 1.

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Friedel-Crafts acylation with N-(trifluoroacetyl)-.alpha.-amino acid chlorides. Application to the preparation of .beta.-arylalkylamines and 3-substituted 1,2,3,4-tetrahydroisoquinolines

Cited by 53 publications

References 1 publication

Synthesis of Chiral TFA-Protected α-Amino Aryl-Ketone Derivatives with Friedel–Crafts Acylation of α-Amino Acid N-Hydroxysuccinimide Ester

Synthesis of Chiral TFA-Protected α-Amino Aryl-Ketone Derivatives with Friedel–Crafts Acylation of α-Amino Acid N-Hydroxysuccinimide Ester

Cyclic α-amino acids as precursors for synthesis of 2-amino-3-hetarylpyrrolin-4-ones and their spiro derivatives

β-Aminoethyltrifluoroborates: Efficient Aminoethylations via Suzuki−Miyaura Cross-Coupling

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