scholarly journals Stereoselective Access to Azetidine-Based α-Aminoacids and Applications to Small Peptides Synthesis

Author(s):  
Felix Reiners ◽  
Emanuel Joseph ◽  
Benedikt Nißl ◽  
Dorian Didier

Recent progress on four-membered ring building blocks has led us to investigate the formation of non-natural azetidine-based amino acids (<i>Aze</i>). A simple organometallic route was developed to access unsaturated carboxylic acids, which were further engaged in metal catalyzed asymmetric reduction. Functionalized <i>Aze</i> derivatives were finally employed in the formation of small peptide chains.

2020 ◽  
Author(s):  
Felix Reiners ◽  
Emanuel Joseph ◽  
Benedikt Nißl ◽  
Dorian Didier

Recent progress on four-membered ring building blocks has led us to investigate the formation of non-natural azetidine-based amino acids (<i>Aze</i>). A simple organometallic route was developed to access unsaturated carboxylic acids, which were further engaged in metal catalyzed asymmetric reduction. Functionalized <i>Aze</i> derivatives were finally employed in the formation of small peptide chains.


Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 391 ◽  
Author(s):  
Ke Cao ◽  
Cai-Yan Zhang ◽  
Tao-Tao Xu ◽  
Ji Wu ◽  
Xin-Yu Wen ◽  
...  

Aromatic heterocycles are ubiquitous building blocks in bioactive natural products, pharmaceutical and agrochemical industries. Accordingly, the carborane-fused heterocycles would be potential candidates in drug discovery, nanomaterials, metallacarboranes, as well as photoluminescent materials. In recent years, the transition metal catalyzed B-H activation has been proved to be an effective protocol for selective functionalization of B-H bond of o-carboranes, which has been further extended for the synthesis of polyhedral borane cluster-fused heterocycles via cascade B-H functionalization/annulation process. This article summarizes the recent progress in construction of polyhedral borane cluster-fused heterocycles via B-H activation.


2020 ◽  
Vol 18 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Hongru Zhang ◽  
Xin Su ◽  
Kaiwu Dong

Hydrocyanation is a powerful method for the preparation of nitriles which are versatile building blocks for the synthesis of amines, acids and amides.


2021 ◽  
Vol 25 ◽  
Author(s):  
João L. P. Ribeiro ◽  
Cláudia Alves ◽  
Ana L. Cardoso ◽  
Susana M. M. Lopes ◽  
Teresa M. V. D. Pinho e Melo

: The asymmetric reduction of oximes and hydrazones is an attractive and versatile strategy for the synthesis of chiral amines, which are valuable building blocks in organic synthesis. This review summarizes the relevant developments made in the last decade on the enantioselective and diastereoselective reduction of oximes and hydrazones involving metal-catalyzed hydrogenation/hydrogenolysis reactions, hydride donor reactions, and electrochemical reactions.


Amino Acids ◽  
2021 ◽  
Vol 53 (2) ◽  
pp. 281-294
Author(s):  
Kim Hoang Yen Duong ◽  
Viktória Goldschmidt Gőz ◽  
István Pintér ◽  
András Perczel

AbstractComplementary to hydrophobic five membered ring β-amino acids (e.g. ACPC), β-sugar amino acids (β-SAAs) have found increasing application as hydrophilic building blocks of foldamers and α/β chimeric peptides. Fmoc-protected β-SAAs [e.g. Fmoc-RibAFU(ip)-OH] are indeed useful Lego elements, ready to use for SPPS. The removal of 1,2-OH isopropylidene protecting group increasing the hydrophilicity of such SAA is presented here. We first used N3-RibAFU(ip)-OH model compound to optimize mild deprotection conditions. The formation of the 1,2-OH free product N3-RibAFU-OH and its methyl glycoside methyl ester, N3-RibAFU(Me)-OMe were monitored by RP-HPLC and found that either 50% TFA or 8 eqv. Amberlite IR-120 H+ resin in MeOH are optimal reagents for the effective deprotection. These conditions were then successfully applied for the synthesis of chimeric oligopeptide: -GG-X-GG- [X=RibAFU(ip)]. We found the established conditions to be effective and—at the same time—sufficiently mild to remove 1,2-O-isopropylidene protection and thus, it is proposed to be used in the synthesis of oligo- and polypeptides of complex sequence combination.


Synthesis ◽  
2020 ◽  
Vol 52 (24) ◽  
pp. 3855-3865
Author(s):  
Ren-Jie Song ◽  
Bin Wei ◽  
Ke-Wei Li ◽  
Yan-Chen Wu ◽  
Shi-Qi Tong

The γ-lactone skeleton is very important component of various natural products, biological molecules, food additives, and perfumes. As a result, much effort has been made towards such compounds. In this review, we summarize recent progress in transition-metal-catalyzed annulation reactions for the formation of γ-lactone derivatives through a radical pathway. Various reagents, such as anhydrides, Togni’s reagent, TMSN3, arenesulfonyl chlorides, arenediazonium salts, dibenzoyl peroxides, O-benzoylhydroxylamine, NFSI, and α-halocarboxylic compounds, used in radical cyclization reactions are described, and the mechanisms of these radical annulation reactions are also discussed.1 Introduction2 Annulations of Alkenes with Anhydrides3 Annulations of Unsaturated Carboxylic Acids with Nucleophiles4 Annulations of Alkenes with α-Halocarboxylic Compounds5 Conclusions and Outlook


Synthesis ◽  
2021 ◽  
Author(s):  
Wei-Wei Liao ◽  
Shu-Qiang Cui

AbstractTransition-metal-catalyzed C–H bond addition to nitriles has emerged as a powerful synthetic approach for the construction of C–C bonds in organic synthesis. Due to the merits of atom- and step-economy, as well the easy availability of the starting materials, these transformations not only deliver acyclic aryl ketone products with nitriles­ as C-building blocks, but can also be utilized for the highly efficient­ assembly of azaheterocyclic skeletons using nitriles as C–N building blocks. This short review summarizes recent progress on transition-metal-catalyzed C–C bond-forming reactions based on C(sp2)–H and C(sp3)–H additions to nitriles.1 Introduction2 Palladium-Catalyzed C–H Addition to Nitriles2.1 Palladium-Catalyzed C–H Addition to Nitriles for the Preparation of Ketone (Imine) Products2.2 Palladium-Catalyzed C–H Addition to Nitriles for the Preparation of Azaheterocycles2.3 Palladium-Catalyzed C–H Addition to Nitriles/1,2-Rearangement3 Other Transition-Metal-Catalyzed C–H Additions to Nitriles4 Summary and Outlook


2016 ◽  
Vol 14 (5) ◽  
pp. 1519-1530 ◽  
Author(s):  
Huawen Huang ◽  
Jinhui Cai ◽  
Guo-Jun Deng

This review is dedicated to showcase and discuss recent progress on N-heterocycle formation by transition-metal catalyzed annulation from O-acyl oximes.


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