Stereoselective Modification of a Cyclopentapeptide via an α-(Ethylthio)glycine Residue

Paulitz, Christian; Steglich, Wölfgang

doi:10.1021/jo971295a

Cited by 31 publications

(8 citation statements)

References 36 publications

(46 reference statements)

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“…Furthermore, phosphazene bases have broad applications in organic synthesis and can be used for Michael addition, [9] alkylation, [10] silylation [11] and heterocumulene [12] reactions. Polyphosphazenes of the type [(RO) 2 P=N] are one of the most studied macromolecules due to both academic and industrial interest.…”

Section: Introductionmentioning

confidence: 99%

A New Class of Chiral Phosphazene Bases: Synthesis and Characterization

et al. 2006

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Chiral examples of phosphazene bases 2a–c were synthesized by treatment of (S)‐2‐(dialkylaminomethyl)pyrrolidine 1a–c, derived from 5‐oxo‐(S)‐proline, with phosphorus pentachloride and subsequent addition of gaseous ammonia. The phosphazenes 2a–c were isolated as HBF4 salts in high yields and fully characterized by 1H, 13C and 31P NMR spectroscopy, various 1D and 2D NMR experiments and mass spectrometry (EI). The molecular structure and the absolute configuration of the salts 2a–c·HBF4 were determined by X‐ray analysis. DFT calculations indicate that 2a is more basic than the Schwesinger base P1 by approximately nine pKa units. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Section: Introductionmentioning

confidence: 99%

A New Class of Chiral Phosphazene Bases: Synthesis and Characterization

et al. 2006

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“…8 But also here, the stereochemical outcome in the modification step could generally not be controlled, except if cyclic and therefore rigid structures were modified. 9 To face this issue of stereocontrol, we decided to investigate reactions of chelated amino acid ester enolates. 10 These enolates can easily be obtained from protected amino acid esters (Scheme 2) (PG = protecting group) via deprotonation with LDA (or LHMDS) and subsequent transmetalation by addition of metal salts (MX n ).…”

Section: Syn Lettmentioning

confidence: 99%

Peptide Modifications: Versatile Tools in Peptide and Natural Product Syntheses

Servatius¹,

Junk²,

Kazmaier³

2019

Synlett

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Peptide modifications via C–C bond formation have emerged as valuable tools for the preparation and alteration of non-proteinogenic amino acids and the corresponding peptides. Modification of glycine subunits in peptides allows for the incorporation of unusual side chains, often in a highly stereoselective manner, orchestrated by the chiral peptide backbone. Moreover, modifications of peptides are not limited to the peptidic backbone. Many side-chain modifications, not only by variation of existing functional groups, but also by C–H functionalization, have been developed over the past decade. This account highlights the synthetic contributions made by our group and others to the field of peptide modifications and their application in natural product syntheses.1 Introduction2 Peptide Backbone Modifications via Peptide Enolates2.1 Chelate Enolate Claisen Rearrangements2.2 Allylic Alkylations2.3 Miscellaneous Modifications3 Side-Chain Modifications3.1 C–H Activation3.1.1 Functionalization via Csp3–H Bond Activation3.2.2 Functionalization via Csp2–H Bond Activation3.2 On Peptide Tryptophan Syntheses4 Conclusion

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“…Contrary to the linear chlorogly-cine analogues good to excellent diastereoselectivities were observed, even with achiral nucleophiles such as water, amines, alcohols and cyanide ( Table 1) [34]. Using the chlorinationelimination-addition sequence numerous different nucleophiles could be reacted with the electrophilic cyclopeptide 40 in moderate to good yields.…”

Section: Peptide Electrophilesmentioning

confidence: 99%

Peptide Backbone Modifications

Kazmaier¹,

Deska

2008

COC

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The selective introduction or manipulation of side chains in a peptide represents a severe synthetic challenge. During the last years numerous different approaches towards the targeted modification of small to medium-sized peptides have been developed which should be presented in this review. Focusing on the manipulation of the peptide backbone, procedures concerning selective N-alkylation, C-alkylation and C=O-thionation are described.

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Stereoselective Modification of a Cyclopentapeptide via an α-(Ethylthio)glycine Residue

Cited by 31 publications

References 36 publications

A New Class of Chiral Phosphazene Bases: Synthesis and Characterization

A New Class of Chiral Phosphazene Bases: Synthesis and Characterization

Peptide Modifications: Versatile Tools in Peptide and Natural Product Syntheses

Peptide Backbone Modifications

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