scholarly journals Macrocyclization of peptidoarylacetamides with self-assembly properties through late-stage palladium-catalyzed C(sp2)▬H olefination

2019 ◽  
Vol 5 (3) ◽  
pp. eaaw0323 ◽  
Author(s):  
Jiantao Tan ◽  
Jie Wu ◽  
Shu Liu ◽  
Hequan Yao ◽  
Huan Wang
Keyword(s):  
Self Assembly ◽  
Late Stage ◽  
Cyclic Peptides ◽  
Cross Link ◽  
Selective Functionalization ◽  
Palladium Catalyzed ◽  
Material Sciences ◽  
Facile Preparation ◽  
Metal Catalyzed ◽  
Site Selective

Peptide macrocycles often display diverse bioactivities and self-assembly properties, which lead to a variety of applications in medicinal and material sciences. Transition metal–catalyzed C▬H activations are emerging strategies for site-selective functionalization of amino acids and peptides, as well as the construction of cyclic peptides. Here, we report the development of a peptide-directed method for the macrocyclization of peptidoarylacetamides by Pd(II)-catalyzed late-stage C(sp2)▬H olefination. In this protocol, peptide backbones act as internal directing groups and enable facile preparation of diverse cyclic peptides that are difficult to synthesize by conventional macrolactamization. Furthermore, we show that the incorporation of aryl-alkene cross-link in the backbone constrains cyclic peptides into conformations for self-assembly.

Theoretical and experimental studies of palladium-catalyzed site-selective C(sp3)−H bond functionalization enabled by transient ligands

2017 ◽  
Author(s):  
Haibo Ge ◽  
Lei Pan ◽  
Piaoping Tang ◽  
Ke Yang ◽  
Mian Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Bond Functionalization ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Mechanistic Investigation ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp<sup>3</sup> carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp<sup>3</sup>)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp<sup>3</sup>)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.<br><br>

Remote C–H Functionalizations by Ruthenium Catalysis

Synthesis ◽  
2021 ◽  
Author(s):  
Korkit Korvorapun ◽  
Ramesh C. Samanta ◽  
Torben Rogge ◽  
Lutz Ackermann
Keyword(s):  
Steric Hindrance ◽  
Late Stage ◽  
Crop Protection ◽  
Full Control ◽  
Site Selectivity ◽  
Important Approach ◽  
Distinct Character ◽  
Ruthenium Catalysis ◽  
Material Sciences ◽  
Site Selective

Synthetic transformations of otherwise inert C–H bonds have emerged as a powerful tool for molecular modifications during the last decades, with broad applications towards pharmaceuticals, material sciences and crop protection. Consistently, a key challenge in C–H activation chemistry is the full control of site-selectivity. In addition to substrate control through steric hindrance or kinetic acidity of C–H bonds, one important approach for the site-selective C–H transformation of arenes is the use of chelation-assistance through directing groups, therefore leading to proximity-induced ortho-C–H metalation. In contrast, more challenging remote C–H activations at the meta- or para-positions continue to be scarce. Within this review, we demonstrate the distinct character of ruthenium catalysis for remote C–H activations until March 2021, highlighting among others late-stage modifications of bio-relevant molecules. Moreover, we highlight important mechanistic insights by experiments and computation, highlighting the key importance of carboxylate-assisted C–H activation with ruthenium(II) complexes.

Late‐Stage Peptide Macrocyclization by Palladium‐Catalyzed Site‐Selective C−H Olefination of Tryptophan

2020 ◽  
Vol 132 (34) ◽  
pp. 14794-14800
Author(s):  
Zengbing Bai ◽  
Chuangxu Cai ◽  
Wangjian Sheng ◽  
Yuxiang Ren ◽  
Huan Wang
Keyword(s):  
Late Stage ◽  
Palladium Catalyzed ◽  
Site Selective

scholarly journals Palladium-Catalyzed Decarbonylative Catellani Reaction

2021 ◽  
Author(s):  
Huixiong Dai ◽  
Ming-Liang Han ◽  
Jun-Jie Chen ◽  
Hui Xu ◽  
Wei Huang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Late Stage ◽  
Aryl Halides ◽  
Potential Utility ◽  
Aromatic Acids ◽  
Alkyl Aryl ◽  
Drug Molecules ◽  
Palladium Catalyzed ◽  
Practical Tool ◽  
Metal Catalyzed

<p><b>The transition metal-catalyzed Catellani reaction of aryl halides has drawn significant attentions as an efficient and practical tool for the synthesis of substituted arenes. We describe herein the palladium-catalyzed, norbornene (NBE)-mediated synthesis of polysubstituted arenes from aromatic acids via decarbonylative Catellani reaction. A variety of alkenyl, alkyl, aryl and sulfur moieties could be conveniently introduced into the<i> ipso</i>-positions of aromatic thioesters. By merging carboxyl-directed C−H functionalization and the classical Catellani reactions, our protocol allowed the construction of 1,2,3-trisubstituted and 1,2,3,4-tetrasubstituted arenes from simple aromatic acids. Furthermore, the late-stage functionalization of a series of drug molecules highlights the potential utility of the reaction.</b></p>

Theoretical and experimental studies of palladium-catalyzed site-selective C(sp3)−H bond functionalization enabled by transient ligands

2017 ◽  
Author(s):  
Haibo Ge ◽  
Lei Pan ◽  
Piaoping Tang ◽  
Ke Yang ◽  
Mian Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Bond Functionalization ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Mechanistic Investigation ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp<sup>3</sup> carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp<sup>3</sup>)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp<sup>3</sup>)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.<br><br>

Backbone-Enabled Peptide Macrocyclization through Late-Stage Palladium-Catalyzed C–H Activation

Synlett ◽  
2019 ◽  
Vol 31 (03) ◽  
pp. 199-204 ◽  
Author(s):  
Zengbing Bai ◽  
Huan Wang
Keyword(s):  
Natural Products ◽  
Small Molecules ◽  
Late Stage ◽  
Cyclic Peptides ◽  
Medicinal Chemistry ◽  
Materials Science ◽  
Three Dimensional ◽  
Chemical Methods ◽  
New Methods ◽  
Palladium Catalyzed

Peptide macrocycles are widely used in fields ranging from medicinal chemistry to materials science. Efficient chemical methods for the synthesis of cyclic peptides with novel three-dimensional structures are highly desired to facilitate the development of this unique class of compounds. However, the range of methods available for constructing peptide macrocycles is limited compared with that for small molecules. We recently developed new methods for synthesizing highly constrained cyclic peptides with C–C crosslinks through Pd-catalyzed C–H activation reactions. These methods use endogenous backbone amides as directing groups and, therefore, have the potential for use in late-stage functionalization of peptide natural products.

Site-Selective, Catalyst-Controlled Alkene Aziridination

Synthesis ◽  
2018 ◽  
Vol 50 (22) ◽  
pp. 4462-4470 ◽  
Author(s):  
Jennifer Schomaker ◽  
Amirah Mat Lani
Keyword(s):  
Transition Metal ◽  
Convenient Method ◽  
Donor Ligands ◽  
Steric Effects ◽  
Silver Complexes ◽  
Selective Catalyst ◽  
Nitrene Transfer ◽  
Selective Functionalization ◽  
Metal Catalyzed ◽  
Site Selective

Transition-metal-catalyzed nitrene transfer is a convenient method to introduce nitrogen into simple substrates through either alkene aziridination or C–H bond amination. Silver complexes have an unusual capability to accommodate a broad range of N-donor ligands and coordination geometries in catalysts competent for nitrene transfer. This behavior has resulted in the ability to achieve tunable chemoselectivity between aziridination and C–H bond amidation, as well as tunable site-selective functionalization between two different C–H bonds. In this paper, efforts to engage the diversity of silver and rhodium catalysts to accomplish selective and tunable aziridination of mixtures of alkenes are discussed. It was found that the selectivity of dinuclear Rh catalysts is dictated largely by steric effects, while the identity of the ligand on silver can be tuned to influence whether the steric or electronic features in the competing alkenes is the primary factor controlling which precursor is preferentially aziridinated.

Arene diversification through distal C(sp2)−H functionalization

Science ◽  
2021 ◽  
Vol 372 (6543) ◽  
pp. eabd5992
Author(s):  
Uttam Dutta ◽  
Sudip Maiti ◽  
Trisha Bhattacharya ◽  
Debabrata Maiti
Keyword(s):  
Transition Metal ◽  
Noncovalent Interactions ◽  
Catalyst Design ◽  
Selective Functionalization ◽  
Directing Group ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal–catalyzed aryl C−H activation is a powerful synthetic tool as it offers step and atom-economical routes to site-selective functionalization. Compared with proximal ortho-C−H activation, distal (meta- and/or para-) C−H activation remains more challenging due to the inaccessibility of these sites in the formation of energetically favorable organometallic pretransition states. Directing the catalyst toward the distal C−H bonds requires judicious template engineering and catalyst design, as well as prudent choice of ligands. This review aims to summarize the recent elegant discoveries exploiting directing group assistance, transient mediators or traceless directors, noncovalent interactions, and catalyst and/or ligand selection to control distal C−H activation.

scholarly journals Palladium-Catalyzed Decarbonylative Catellani Reaction

2021 ◽  
Author(s):  
Huixiong Dai ◽  
Ming-Liang Han ◽  
Jun-Jie Chen ◽  
Hui Xu ◽  
Wei Huang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Late Stage ◽  
Aryl Halides ◽  
Potential Utility ◽  
Aromatic Acids ◽  
Alkyl Aryl ◽  
Drug Molecules ◽  
Palladium Catalyzed ◽  
Practical Tool ◽  
Metal Catalyzed

<p><b>The transition metal-catalyzed Catellani reaction of aryl halides has drawn significant attentions as an efficient and practical tool for the synthesis of substituted arenes. We describe herein the palladium-catalyzed, norbornene (NBE)-mediated synthesis of polysubstituted arenes from aromatic acids via decarbonylative Catellani reaction. A variety of alkenyl, alkyl, aryl and sulfur moieties could be conveniently introduced into the<i> ipso</i>-positions of aromatic thioesters. By merging carboxyl-directed C−H functionalization and the classical Catellani reactions, our protocol allowed the construction of 1,2,3-trisubstituted and 1,2,3,4-tetrasubstituted arenes from simple aromatic acids. Furthermore, the late-stage functionalization of a series of drug molecules highlights the potential utility of the reaction.</b></p>

Late‐Stage Peptide Macrocyclization by Palladium‐Catalyzed Site‐Selective C−H Olefination of Tryptophan

2020 ◽  
Vol 59 (34) ◽  
pp. 14686-14692 ◽  
Author(s):  
Zengbing Bai ◽  
Chuangxu Cai ◽  
Wangjian Sheng ◽  
Yuxiang Ren ◽  
Huan Wang
Keyword(s):  
Late Stage ◽  
Palladium Catalyzed ◽  
Site Selective
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