Synthesis and characterization of chiral di(N-protected-α-amino)diazo-β-diketones from α-diazoketones and imidazolides derived from amino acids

Saraireh, Ibrahim A. M.

doi:10.1016/j.tetlet.2012.01.093

Cited by 7 publications

(5 citation statements)

References 14 publications

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“…63 Diazoketones derived from protected enantiopure amino acids were also successfully condensed (Scheme 24) with acyl imidazolide in the presence of LDA to afford the corresponding bis(N-protected α-amino)diazo-α-diketones. 64 2.3.3. Electrophilic Substitution with Silyl Chlorides as a Protecting Group Strategy.…”

Section: Acylation Of Diazoalkanes 12mentioning

confidence: 99%

“…Deprotonation of diazocarbonyls and subsequent C–C bond formation has been carried out with electrophiles other than aldehydes and imines, such as chloroformates, pyrocarbonates, and sulfonyl chlorides (Scheme ). Diazoketones derived from protected enantiopure amino acids were also successfully condensed (Scheme ) with acyl imidazolide in the presence of LDA to afford the corresponding bis(N-protected α-amino)diazo-α-diketones …”

Section: Synthesis Of α-Diazocarbonyl Compoundsmentioning

confidence: 99%

See 1 more Smart Citation

Modern Organic Synthesis with α-Diazocarbonyl Compounds

Ford¹,

Miel

Ring³

et al. 2015

Chem. Rev.

1,374

585

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Section: Acylation Of Diazoalkanes 12mentioning

confidence: 99%

Section: Synthesis Of α-Diazocarbonyl Compoundsmentioning

confidence: 99%

Modern Organic Synthesis with α-Diazocarbonyl Compounds

Ford¹,

Miel

Ring³

et al. 2015

Chem. Rev.

1,374

585

View full text Add to dashboard Cite

“…α-Diazoketones were prepared according to the literature method. − The corresponding acyl halides (8 mmol, 1 equiv) were added dropwise to ethereal solution of diazomethane (0.4 M, 20 mmol, 2.5 equiv, 50 mL) at 0 °C and the crude reaction mixture was warmed to room temperature and stirred for 2 h. After that, the solvent was removed under vacuum and the residue purified by flash column chromatography (hexane/EtOAC 9:1) to afford diazoketones 2a – h . Diazoketones 2j and 2k were prepared via mixed anhydrides.…”

Section: Methodsmentioning

confidence: 99%

Metal-Free Insertion Reactions of Diazo Carbonyls to Azlactones

et al. 2018

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Insertion reactions of diazo carbonyls to azlactones in basic conditions have been performed. The developed method allows the preparation of a wide range of oxazole derivatives in yields ranging from 74 to 98%. Different substituents on both azlactone rings and diazo carbonyls do not compromise the methodology, even those containing stereogenic centers. Isotopic labeling experiments revealed the mechanism may proceed through a rare diazo carbonyl activation by an ammonium salt derivative.

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“…More recently, other papers directed toward the synthesis and application of N-Z-protected α-amino diazoketones have been published. 42,43 The studies previously cited also reveal that all the known methods suffer from a delicate balance between both processes of diazotization and Cmethyl ester formation, depending on the temperature, addition rate, and stability of the employed reagents. Hence, many approaches do not seem to be ideal for the efficient and versatile synthesis of chiral N-Fmoc-α-amino diazoketones.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Besides, commercial triphenylphosphine must be purified by recrystallyzation prior the use in order to enhance its reactivity, and triphenylphosphine oxide formed as a reaction side-product cannot perfectly be removed also by column chromatography. More recently, other papers directed toward the synthesis and application of N - Z -protected α-amino diazoketones have been published. , The studies previously cited also reveal that all the known methods suffer from a delicate balance between both processes of diazotization and C -methyl ester formation, depending on the temperature, addition rate, and stability of the employed reagents. Hence, many approaches do not seem to be ideal for the efficient and versatile synthesis of chiral N -Fmoc-α-amino diazoketones.…”

Section: Introductionmentioning

confidence: 99%

A One-Pot Procedure for the Preparation ofN-9-Fluorenylmethyloxycarbonyl-α-amino Diazoketones from α-Amino Acids

et al. 2012

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The study describes a new "one-pot" route to the synthesis of N-9-fluorenylmethyloxycarbonyl (Fmoc) α-amino diazoketones. The procedure was tested on a series of commercially available free or side-chain protected α-amino acids employed as precursors. The conversion into the title compounds was achieved by masking and activating the α-amino acids with a single reagent, namely, 9-fluorenylmethyl chloroformate (Fmoc-Cl). The resulting N-protected mixed anhydrides were reacted with diazomethane to lead to the α-amino diazoketones, which were isolated by flash column chromatography in very good to excellent overall yields. The versatility of the procedure was verified on lipophilic α-amino acids and further demonstrated by the preparation of N-Fmoc-α-amino diazoketones also from α-amino acids containing side-chain masking groups, which are orthogonal to the Fmoc one. The results confirmed that tert-butyloxycarbonyl (Boc), tert-butyl ((t)Bu), and 2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl (Pbf), three acid-labile protecting groups mostly adopted in the solution and solid-phase peptide synthesis, are compatible to the adopted reaction conditions. In all cases, the formation of the corresponding C-methyl ester of the starting amino acid was not observed. Moreover, the proposed method respects the chirality of the starting α-amino acids. No racemization occurred when the procedure was applied to the synthesis of the respective N-Fmoc-protected α-amino diazoketones from L-isoleucine and L-threonine and to the preparation of a diastereomeric pair of N-Fmoc-protected dipeptidyl diazoketones.

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Synthesis and characterization of chiral di(N-protected-α-amino)diazo-β-diketones from α-diazoketones and imidazolides derived from amino acids

Cited by 7 publications

References 14 publications

Modern Organic Synthesis with α-Diazocarbonyl Compounds

Modern Organic Synthesis with α-Diazocarbonyl Compounds

Metal-Free Insertion Reactions of Diazo Carbonyls to Azlactones

A One-Pot Procedure for the Preparation ofN-9-Fluorenylmethyloxycarbonyl-α-amino Diazoketones from α-Amino Acids

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