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.

Reversing Reactivity: Stereoselective Desulfurative β-O-Glycosylation of Anomeric Thiosugars with Carboxylic Acids Under Copper or Cobalt Catalysis

2019 ◽  
Author(s):  
Samir Messaoudi ◽  
Nedjwa Bennai ◽  
Amelie Chabrier ◽  
Maha Fatthalla ◽  
Expédite Yen-Pon ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Late Stage ◽  
Catalytic Amount ◽  
Broad Scope ◽  
Wide Range ◽  
Glycosylation Reaction

We have discovered a new mode of reactivity of 1-thiosugars in the presence of Cu(II) or Co(II) for a stereoselective <i>O</i>-glycosylation reaction. The process involves the use of a catalytic amount of Cu(acac)2 or Co(acac)2 and Ag2CO3 as an oxidant in α,α,α-trifluorotoluene (TFT). Moreover, this protocol turned out to have a broad scope, allowing to prepare a wide range of com-plex substituted <i>O</i>-glycoside esters in good to excellent yields with an exclusive β-selectivity. The late-stage modification of phar-maceuticals by this method was also demonstrated.

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>

SN2-Type Glycosylation with Unprotected Pyranoses

2019 ◽  
Author(s):  
Hironori Takeuchi ◽  
Yusuke Fujimori ◽  
Hiromitsu Shibayama ◽  
Masaru Nagaishi ◽  
Yoshihiro Ueda ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Antitumor Activity ◽  
Benzoic Acid ◽  
Total Synthesis ◽  
Carboxylic Acids ◽  
Stereoselective Glycosylation ◽  
Wide Range ◽  
High Stereoselectivity ◽  
Glycosyl Donors

<p>An SN2 mechanism was proposed for highly stereoselective glycosylation of benzoic acid with unprotected α-D-glucose under Mitsunobu conditions in dioxane, while an SN1 mechanism seems to be responsible for non-stereoselective glycosylation in DMF. The SN2-type glycosylation can be applicable to various unprotected pyranoses as glycosyl donors and a wide range of carboxylic acids, phenols, and imides as glycosyl acceptors, retaining its high stereoselectivity (34 examples). Glycosylation of a carboxylic acid with unprotected α-D-mannose proceeded also in an SN2 manner to directly afford a usually less accessible 1,2-<i>cis</i>-mannoside. An extremely short-step total synthesis of a middle molecule (1874 Da) natural glycoside with antitumor activity, coriariin A, was achieved via a double SN2 glycosylation strategy with two molecules of unprotected α-D-glucose.</p>

Reversing Reactivity: Stereoselective Desulfurative β-O-Glycosylation of Anomeric Thiosugars with Carboxylic Acids Under Copper or Cobalt Catalysis

2019 ◽  
Author(s):  
Samir Messaoudi ◽  
Nedjwa Bennai ◽  
Amelie Chabrier ◽  
Maha Fatthalla ◽  
Expédite Yen-Pon ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Late Stage ◽  
Catalytic Amount ◽  
Broad Scope ◽  
Wide Range ◽  
Glycosylation Reaction

We have discovered a new mode of reactivity of 1-thiosugars in the presence of Cu(II) or Co(II) for a stereoselective <i>O</i>-glycosylation reaction. The process involves the use of a catalytic amount of Cu(acac)2 or Co(acac)2 and Ag2CO3 as an oxidant in α,α,α-trifluorotoluene (TFT). Moreover, this protocol turned out to have a broad scope, allowing to prepare a wide range of com-plex substituted <i>O</i>-glycoside esters in good to excellent yields with an exclusive β-selectivity. The late-stage modification of phar-maceuticals by this method was also demonstrated.

Highly efficient conversion of aldehydes to carboxylic acid in the presence of platinum porphyrin sensitizers, air and sunlight

2012 ◽  
Vol 16 (01) ◽  
pp. 93-100 ◽  
Author(s):  
Mahdi Hajimohammadi ◽  
Hamid Mofakham ◽  
Nasser Safari ◽  
Anahita Mortazavi Manesh
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Free Base ◽  
Aliphatic Aldehydes ◽  
Mild Conditions ◽  
Efficient Conversion ◽  
Highly Efficient ◽  
Wide Range ◽  
Platinum Porphyrin

A variety of aromatic and aliphatic aldehydes were oxidized to the corresponding carboxylic acids in the presence of platinum porphyrin, sunlight and air in acetonitrile solvent under mild conditions. Nitrobenzaldehydes were found to be very efficient 1O2 scavengers that quench the formation of acids from any aldehyde in the presence of free-base porphyrin sensitizers. However, nitrobenzaldehydes were converted to the corresponding acids in the presence of platinum porphyrins. The platinum porphyrins are very good and efficient catalysts for a wide range of applications in the aerobic conversion of aldehydes to acids.

scholarly journals Photoredox of Gem-Diborylalkenes: A Novel Reactivity Toward Diverse 1,1-Bisborylalkanes

2019 ◽  
Author(s):  
Nivesh Kumar ◽  
Nadim Eghbarieh ◽  
Tamar Stein ◽  
Alexander Shames ◽  
Ahmad Masarwa
Keyword(s):  
Late Stage ◽  
Organic Molecules ◽  
Boron Compound ◽  
Bioactive Molecules ◽  
Radical Intermediates ◽  
First Time

The use of <i>gem-bis</i>-metalated-alkenes, i.e., vinyl <i>gemdi</i>boron-compound, as light-labile substrates is explored for the first time. The knowledge gained provided us with an in-depth understanding of the reactivity of novel radical intermediates of <i>geminal</i>-metalated ethane. This methodology can serve as the late-stage diversification of bioactive molecules and simple organic molecules in which it drives the synthesis of gemdiborylalkanes.

scholarly journals Photoredox of Gem-Diborylalkenes: A Novel Reactivity Toward Diverse 1,1-Bisborylalkanes

2019 ◽  
Author(s):  
Nivesh Kumar ◽  
Nadim Eghbarieh ◽  
Tamar Stein ◽  
Alexander Shames ◽  
Ahmad Masarwa
Keyword(s):  
Late Stage ◽  
Organic Molecules ◽  
Boron Compound ◽  
Bioactive Molecules ◽  
Radical Intermediates ◽  
First Time

The use of <i>gem-bis</i>-metalated-alkenes, i.e., vinyl <i>gemdi</i>boron-compound, as light-labile substrates is explored for the first time. The knowledge gained provided us with an in-depth understanding of the reactivity of novel radical intermediates of <i>geminal</i>-metalated ethane. This methodology can serve as the late-stage diversification of bioactive molecules and simple organic molecules in which it drives the synthesis of gemdiborylalkanes.

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>

SN2-Type Glycosylation with Unprotected Pyranoses

2019 ◽  
Author(s):  
Hironori Takeuchi ◽  
Yusuke Fujimori ◽  
Hiromitsu Shibayama ◽  
Masaru Nagaishi ◽  
Yoshihiro Ueda ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Antitumor Activity ◽  
Benzoic Acid ◽  
Total Synthesis ◽  
Carboxylic Acids ◽  
Stereoselective Glycosylation ◽  
Wide Range ◽  
High Stereoselectivity ◽  
Glycosyl Donors

<p>An SN2 mechanism was proposed for highly stereoselective glycosylation of benzoic acid with unprotected α-D-glucose under Mitsunobu conditions in dioxane, while an SN1 mechanism seems to be responsible for non-stereoselective glycosylation in DMF. The SN2-type glycosylation can be applicable to various unprotected pyranoses as glycosyl donors and a wide range of carboxylic acids, phenols, and imides as glycosyl acceptors, retaining its high stereoselectivity (34 examples). Glycosylation of a carboxylic acid with unprotected α-D-mannose proceeded also in an SN2 manner to directly afford a usually less accessible 1,2-<i>cis</i>-mannoside. An extremely short-step total synthesis of a middle molecule (1874 Da) natural glycoside with antitumor activity, coriariin A, was achieved via a double SN2 glycosylation strategy with two molecules of unprotected α-D-glucose.</p>

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