scholarly journals Site-Selective Alkoxylation of Benzylic C–H Bonds via Photoredox Catalysis

2019 ◽  
Author(s):  
Byung Joo Lee ◽  
kimberly deglopper ◽  
Tehshik Yoon
Keyword(s):  
Late Stage ◽  
Functional Group ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Site Selectivity ◽  
Wide Range ◽  
High Site ◽  
Alkoxy Groups ◽  
Site Selective ◽  
Mediated Oxidation

<div> <div> <div> <p>There are relatively few methods that accom- plish the selective alkoxylation of sp3-hybridized C–H bonds, particularly in comparison to the numerous analogous strate- gies for C–N and C–C bond formation. We report a photo- catalytic protocol for the functionalization of benzylic C–H bonds with a wide range of readily available oxygen nucleo- philes. Our strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C–O bonds with high site selectivity, chemoselectivity, and functional group tolerance. This method enables the late- stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential appli- cations in synthesis and medicinal chemistry. </p> </div> </div> </div>

scholarly journals Site-Selective Alkoxylation of Benzylic C–H Bonds via Photoredox Catalysis

2019 ◽  
Author(s):  
Byung Joo Lee ◽  
kimberly deglopper ◽  
Tehshik Yoon
Keyword(s):  
Late Stage ◽  
Functional Group ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Site Selectivity ◽  
Wide Range ◽  
High Site ◽  
Alkoxy Groups ◽  
Site Selective ◽  
Mediated Oxidation

<div> <div> <div> <p>There are relatively few methods that accom- plish the selective alkoxylation of sp3-hybridized C–H bonds, particularly in comparison to the numerous analogous strate- gies for C–N and C–C bond formation. We report a photo- catalytic protocol for the functionalization of benzylic C–H bonds with a wide range of readily available oxygen nucleo- philes. Our strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C–O bonds with high site selectivity, chemoselectivity, and functional group tolerance. This method enables the late- stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential appli- cations in synthesis and medicinal chemistry. </p> </div> </div> </div>

scholarly journals Site-Selective Alkoxylation of Benzylic C–H Bonds via Photoredox Catalysis

2019 ◽  
Author(s):  
Byung Joo Lee ◽  
kimberly deglopper ◽  
Tehshik Yoon
Keyword(s):  
Late Stage ◽  
Functional Group ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Site Selectivity ◽  
Wide Range ◽  
High Site ◽  
Alkoxy Groups ◽  
Site Selective ◽  
Mediated Oxidation

<div> <div> <div> <p>There are relatively few methods that accom- plish the selective alkoxylation of sp3-hybridized C–H bonds, particularly in comparison to the numerous analogous strate- gies for C–N and C–C bond formation. We report a photo- catalytic protocol for the functionalization of benzylic C–H bonds with a wide range of readily available oxygen nucleo- philes. Our strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C–O bonds with high site selectivity, chemoselectivity, and functional group tolerance. This method enables the late- stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential appli- cations in synthesis and medicinal chemistry. </p> </div> </div> </div>

Palladium-catalyzed site-selective arylation of aliphatic ketones enabled by a transient ligand

2018 ◽  
Vol 54 (22) ◽  
pp. 2759-2762 ◽  
Author(s):  
Lei Pan ◽  
Ke Yang ◽  
Guigen Li ◽  
Haibo Ge
Keyword(s):  
Functional Group ◽  
Direct Arylation ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Palladium Catalyzed ◽  
High Site ◽  
Site Selective

A direct arylation of C–H bonds of ketones enabled by a cheap and commercially available transient ligand with high site-selectivity and functional group compatibility is reported.

scholarly journals Tyrosine and Drug-like Late-stage Benzylic Functionalization via Photoredox Catalysis

2020 ◽  
Author(s):  
Tobias Brandhofer ◽  
Volker Derdau ◽  
María Mendez ◽  
Christoph Pöverlein ◽  
Olga Garcia Mancheno
Keyword(s):  
Natural Products ◽  
Visible Light ◽  
Late Stage ◽  
Medicinal Chemistry ◽  
Functional Group ◽  
Reaction Conditions ◽  
Site Selectivity ◽  
Wide Range ◽  
High Yields ◽  
Therapeutic Compounds

Abstract Visible light mediated late-stage functionalization is a rising field in synthetic and medicinal chemistry, allowing the fast and diversified modification of valuable, potentially therapeutic compounds such as peptides. However, there are relatively few mild methodologies for the C(sp3)-H functionalization of complex peptides. Herein, we report a visible light mediated photocatalytic protocol for the benzylic C-H modification of tyrosine and related C-H bonds. The embraced radical-cation/deprotonation strategy enables an incorporation of a wide range of valuable functional groups in high yields and chemoselectivity. The mild reaction conditions, site-selectivity and high functional group tolerance was highlighted by the functionalization of complex peptides, drugs and natural products, providing a promising synthetic platform in medicinal chemistry.

Ru-Catalyzed highly site-selective C–H bond arylation of 9-(pyrimidin-2-yl)-9H-carbazole

RSC Advances ◽  
2016 ◽  
Vol 6 (59) ◽  
pp. 54431-54434 ◽  
Author(s):  
K. Harsha Vardhan Reddy ◽  
R. Uday Kumar ◽  
V. Prakash Reddy ◽  
G. Satish ◽  
Jagadeesh Babu Nanubolu ◽  
...  
Keyword(s):  
Functional Group ◽  
Boronic Acids ◽  
Site Selectivity ◽  
High Site ◽  
Site Selective

We describe an efficient ruthenium-catalyzed C–H bond ortho-arylation of 9-(pyrimidin-2-yl)-9H-carbazole using boronic acids. This methodology exhibits excellent and high site-selectivity, functional group tolerance and gave the desired product in moderate to good yields.

scholarly journals Kinetic resolution of indolines by asymmetric hydroxylamine formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gang Wang ◽  
Ran Lu ◽  
Chuangchuang He ◽  
Lei Liu
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Synthesis ◽  
Late Stage ◽  
Kinetic Resolution ◽  
High Efficiency ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Environmentally Benign ◽  
Secondary Amines

AbstractCatalytic kinetic resolution of amines represents a longstanding challenge in chemical synthesis. Here, we described a kinetic resolution of secondary amines through oxygenation to produce enantiopure hydroxylamines involving N–O bond formation. The economic and practical titanium-catalyzed asymmetric oxygenation with environmentally benign hydrogen peroxide as oxidant is applicable to a range of racemic indolines with multiple stereocenters and diverse substituent patterns in high efficiency with efficient chemoselectivity and enantio-discrimination. Late-stage asymmetric oxygenation of bioactive molecules that are otherwise difficult to synthesize was also explored.

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.

scholarly journals Late-Stage β-C(sp3)–H Deuteration of Carboxylic Acids

2021 ◽  
Author(s):  
Alexander Uttry ◽  
Sourjya Mal ◽  
Manuel van Gemmeren
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Late Stage ◽  
Bioactive Molecules ◽  
Wide Range ◽  
Catalyst Systems ◽  
First Time

Carboxylic acid moieties are highly abundant in bioactive molecules. In this study we describe the late-stage β-C(sp<sup>3</sup>)–H deuteration of free carboxylic acids. Based on our finding that the C–H activation with our catalyst systems is reversible, the de-deuteration process was first optimized. The resulting conditions involve ethylenediamine-based ligands, which, amongst other positions, for the first time enables the functionalization of non-activated methylene β-C(sp<sup>3</sup>)–H bonds and can be used to achieve the desired deuteration when using a deuterated solvent. The reported method allows for the functionalization of a wide range of free carboxylic acids with diverse substitution patterns, as well as the late-stage deuteration of bioactive molecules and related frameworks.

Non-directed highly para-selective C-H functionalization of TIPS-protected phenols promoted by a proton shuttle

2021 ◽  
Author(s):  
Jingyao Geng ◽  
Zhang Fang ◽  
Guangliang Tu ◽  
Yingsheng Zhao
Keyword(s):  
Bioactive Molecules ◽  
Protecting Group ◽  
Mechanism Study ◽  
Phenol Derivatives ◽  
Site Selectivity ◽  
Palladium Catalyzed ◽  
Direct Functionalization ◽  
Poor Site ◽  
Site Selective ◽  
First Time

Abstract Palladium-catalyzed non-directed C-H functionalization provides an efficient approach for direct functionalization of arenes, but it usually suffers from poor site selectivity, limiting its wide application. Herein, it is reported for the first time that the proton shuttle of 3,5-dimethyladamantane-1-carboxylic acid (1-DMAdCO2H) can affect the site selectivity during the C-H activation step in palladium-catalyzed non-directed C-H functionalization, leading to highly para-selective C-H olefination of TIPS-protected phenols. This transformation displayed good generality in realizing various other para-selective C-H functionalization reactions such as hydroxylation, halogenation, and allylation reactions. A wide variety of phenol derivatives including bioactive molecules of triclosan, thymol, and propofol, were compatible substrates, leading to the corresponding para-selective products in moderate to good yields. A preliminary mechanism study revealed that the spatial repulsion factor between proton shuttle and bulky protecting group resulted in the selective C-H activation at the less sterically hindered para-position. This new model non-directed para-selective C-H functionalization can provide a straightforward route for remote site-selective C-H activations.

scholarly journals A general method for site-selective Csp3–S bond formation via cooperative catalysis

2020 ◽  
Vol 11 (5) ◽  
pp. 1276-1282 ◽  
Author(s):  
Yuman Qin ◽  
Yujie Han ◽  
Yongzhen Tang ◽  
Junfa Wei ◽  
Mingyu Yang
Keyword(s):  
Functional Group ◽  
Bond Formation ◽  
Aliphatic Amines ◽  
Cooperative Catalysis ◽  
Site Selective ◽  
General Method

A copper-catalyzed site-selective thiolation of Csp3–H bonds of aliphatic amines was developed. The method features a broad substrate scope and good functional group tolerance.

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