scholarly journals Visible-Light, Iodine-Promoted Formation of N-Sulfonyl Imines and N-Alkylsulfonamides from Aldehydes and Hypervalent Iodine Reagents

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1838 ◽  
Author(s):  
Megan Hopkins ◽  
Zachary Brandeburg ◽  
Andrew Hanson ◽  
Angus Lamar
Keyword(s):  
Drug Discovery ◽  
Visible Light ◽  
Initial Step ◽  
Hypervalent Iodine ◽  
Mechanistic Studies ◽  
Synthetic Methodology ◽  
Reaction Conditions ◽  
Drug Discovery And Development ◽  
Radical Initiator ◽  
Reaction Proceeds

Alternative synthetic methodology for the direct installation of sulfonamide functionality is a highly desirable goal within the domain of drug discovery and development. The formation of synthetically valuable N-sulfonyl imines from a range of aldehydes, sulfonamides, and PhI(OAc)2 under practical and mild reaction conditions has been developed. According to mechanistic studies described within, the reaction proceeds through an initial step involving a radical initiator (generated either by visible-light or heat) to activate the reacting substrates. The reaction provides a synthetically useful and operationally simple, relatively mild alternative to the traditional formation of N-sulfonyl imines that utilizes stable, widely available reagents.

scholarly journals Intermolecular 3+3 Ring Expansion of Aziridines to Dehydropiperidines through the Intermediacy of Aziridinium Ylides

2019 ◽  
Author(s):  
Jennifer Schomaker ◽  
Josephine Eshon ◽  
Kate A. Nicastri ◽  
Steven C. Schmid ◽  
William T. Raskopf ◽  
...  
Keyword(s):  
Natural Product ◽  
Functional Group ◽  
Ring Expansion ◽  
Sigmatropic Rearrangement ◽  
Reactive Intermediate ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Complex Molecules ◽  
Form Complex ◽  
Reaction Proceeds

Bicyclic aziridines undergo formal [3+3] ring expansion reactions when exposed to rhodium-bound vinyl carbenes to form complex dehydropiperidines in a highly stereocontrolled rearrangement. Mechanistic studies and DFT computations indicate the reaction proceeds through the formation of a vinyl aziridinium ylide; this reactive intermediate undergoes a concerted, asynchronous, pseudo-[1,4]- sigmatropic rearrangement to directly furnish the heterocyclic products with net retention at the new C-C bond. In combination with an asymmetric silver-catalyzed aziridination developed in our group, this method quickly delivers enantioenriched scaffolds with up to three contiguous stereocenters. The mild reaction conditions, functional group tolerance, and high stereochemical retention of this method are especially well-suited for appending piperidine motifs to natural product and complex molecules. Ultimately, our work establishes the value of underutilized aziridinium ylides as key intermediates in strategies to convert small, strained rings to larger N-heterocycles.

scholarly journals Palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides

2017 ◽  
Vol 13 ◽  
pp. 2610-2616 ◽  
Author(s):  
Tao Fan ◽  
Wei-Dong Meng ◽  
Xingang Zhang
Keyword(s):  
Alkyl Radical ◽  
Functional Group ◽  
High Efficiency ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Type Reaction ◽  
Alkyl Bromides ◽  
Reaction Proceeds ◽  
Palladium Catalyzed ◽  
Hydroxy Groups

An efficient palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides has been developed. The reaction proceeds under mild reaction conditions with high efficiency and excellent functional group tolerance, even towards formyl and hydroxy groups. Preliminary mechanistic studies reveal that a secondary trifluoromethylated alkyl radical is involved in the reaction.

Mechanistic studies and optimisation of a Pd-catalysed direct arylation reaction using phosphine-free systems

2015 ◽  
Vol 2 (5) ◽  
pp. 520-525 ◽  
Author(s):  
Junpei Kuwabara ◽  
Masaru Sakai ◽  
Qiao Zhang ◽  
Takaki Kanbara
Keyword(s):  
Initial Step ◽  
Mechanistic Study ◽  
Valuable Insight ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Direct Arylation

The mechanistic study of the initial step in direct arylation provides valuable insight for optimising reaction conditions.

Visible-Light-Promoted C2 Trifluoromethylation of Quinoline N-Oxides

Synthesis ◽  
2019 ◽  
Vol 52 (02) ◽  
pp. 219-226 ◽  
Author(s):  
Ce Liang ◽  
Wang-Tao Zhuo ◽  
Yan-Ning Niu ◽  
Guo-Lin Gao
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Room Temperature ◽  
Efficient Synthesis ◽  
Mechanistic Studies ◽  
Reaction Proceeds

A photoredox catalytic strategy has been described for the direct C2 trifluoromethylation of quinoline N-oxides. This reaction is compatible with a range of synthetically relevant functional groups for providing efficient synthesis of a variety of C2 trifluoromethyl quinoline N-oxides at room temperature. Mechanistic studies indicated that the reaction proceeds via a radical pathway.

BODIPY catalyzed amide synthesis promoted by BHT and air under visible light

2016 ◽  
Vol 14 (29) ◽  
pp. 7028-7037 ◽  
Author(s):  
Xiao-Fei Wang ◽  
Shu-Sheng Yu ◽  
Chao Wang ◽  
Dong Xue ◽  
Jianliang Xiao
Keyword(s):  
Visible Light ◽  
Aromatic Aldehydes ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Amide Synthesis ◽  
Oxidative Amidation

A novel and efficient protocol for the synthesis of amides is reported via a BODIPY catalyzed oxidative amidation of aromatic aldehydes under visible light, with broad substrate scope and mild reaction conditions. Mechanistic studies reveal that dioxygen could be activated through both an ET and SET pathway to form the active peroxide intermediates.

scholarly journals Visible-Light-Mediated Synthesis of Trifluoromethylthiolated Arenes

Synthesis ◽  
2018 ◽  
Vol 51 (14) ◽  
pp. 2865-2870 ◽  
Author(s):  
Clément Ghiazza ◽  
Cyrille Monnereau ◽  
Lhoussain Khrouz ◽  
Thierry Billard ◽  
Anis Tlili
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Reaction Conditions ◽  
Reaction Proceeds ◽  
Stable Reagent ◽  
Shelf Stable

The visible-light-mediated synthesis of trifluoromethylthiolated arenes in the presence of ruthenium-based photocatayst under mild reaction conditions is reported. The trifluoromethylthiolated arenes are obtained using the shelf-stable reagent trifluoromethyl toluenethiosulfonate at room temperature. The reaction proceeds selectively and does not require the presence of any additive. A mechanism is proposed based on the obtained results of EPR as well as luminescence

scholarly journals Intermolecular 3+3 Ring Expansion of Aziridines to Dehydropiperidines through the Intermediacy of Aziridinium Ylides

2019 ◽  
Author(s):  
Jennifer Schomaker ◽  
Josephine Eshon ◽  
Kate A. Nicastri ◽  
Steven C. Schmid ◽  
William T. Raskopf ◽  
...  
Keyword(s):  
Natural Product ◽  
Functional Group ◽  
Ring Expansion ◽  
Sigmatropic Rearrangement ◽  
Reactive Intermediate ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Complex Molecules ◽  
Form Complex ◽  
Reaction Proceeds

Bicyclic aziridines undergo formal [3+3] ring expansion reactions when exposed to rhodium-bound vinyl carbenes to form complex dehydropiperidines in a highly stereocontrolled rearrangement. Mechanistic studies and DFT computations indicate the reaction proceeds through the formation of a vinyl aziridinium ylide; this reactive intermediate undergoes a concerted, asynchronous, pseudo-[1,4]- sigmatropic rearrangement to directly furnish the heterocyclic products with net retention at the new C-C bond. In combination with an asymmetric silver-catalyzed aziridination developed in our group, this method quickly delivers enantioenriched scaffolds with up to three contiguous stereocenters. The mild reaction conditions, functional group tolerance, and high stereochemical retention of this method are especially well-suited for appending piperidine motifs to natural product and complex molecules. Ultimately, our work establishes the value of underutilized aziridinium ylides as key intermediates in strategies to convert small, strained rings to larger N-heterocycles.

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