The formation of carbon-carbon (C-C) bonds is a cornerstone of organic synthesis. Among various methods to construct Csp-Csp bonds, the reductive Heck reaction between (hetero)aryl halides and alkenes stands out due to its potential efficiency and broad substrate availability. However, traditional reductive Heck reactions are limited by the use of precious metal catalysts and/or limited aryl halide and alkene compatibility. Here, we present an electrochemically mediated, metal- and catalyst-free reductive Heck reaction that tolerates both unactivated (hetero)aryl halides and diverse alkenes such as vinyl boronates and silanes. Detailed electrochemical and deuterium-labeling studies support that this transformation likely proceeds through a paired electrolysis pathway, in which acid generated by the oxidation of N,N-diisopropylethylamine (DIPEA) at the anode intercepts an alkyl carbanion formed after radical-polar crossover at the cathode. As such, this approach offers a sustainable method for the construction of Csp-Csp bonds from (hetero)aryl halides and alkenes, paving the way for the development of other electrochemically mediated olefin difunctionalization reactions.
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http://dx.doi.org/10.1002/anie.202408834 | DOI Listing |
Chem Sci
December 2024
Department of Chemistry, Korea Advanced Institute of Science & Technology (KAIST) Daejeon 34141 Republic of Korea
Securinega alkaloids, known for their unique structures and neuroplasticity-inducing potential, are promising candidates for treating neurodegenerative diseases such as depression and substance use disorders (SUD). Herein, we delineate the total synthesis of two dimeric Rauhut-Currier (RC) reaction-based securinega alkaloids, (-)-flueggenine A and (-)-15'--flueggenine D. The key step involved a novel reductive Heck dimerization strategy, utilizing a silyl-tethered enone coupling partner to ensure the desired reactivity and stereoselectivity.
View Article and Find Full Text PDFBiomacromolecules
December 2024
Chair of Macromolecular Chemistry, Julius-Maximilians-Universität Würzburg, Röntgenring 11, 97070 Würzburg, Germany.
Postpolymerization modifications are valuable techniques for creating functional polymers that are challenging to synthesize directly. This study presents aliphatic polycarbonates with pendant thiol-reactive groups for disulfide formation with mercaptans. The reductive responsive nature of this reaction allows for reversible postpolymerization modifications on biodegradable scaffolds.
View Article and Find Full Text PDFACS Omega
November 2024
Department of Chemistry, Jadavpur University, Kolkata 700032, India.
Herein, a nickel-catalyzed divergent reductive-Heck reaction of 1-bromo-2-((2-(aryl/alkyl ethynyl)phenoxy)methyl)benzene and 2-(aryl/alkyl ethynyl)phenyl 2-bromobenzenesulfonate derivatives has been demonstrated through the regulation of reducing agents and solvent systems. This scalable protocol offers regio- and stereoselective access to functionalized dibenzo[,]oxepine and dibenzo[,][1,2]oxathiepine 6,6-dioxide scaffolds in high to excellent yields under a mild set of reaction conditions. This methodology offers a predictable route for the synthesis of medium ring oxygen heterocycles and demonstrates wide substrate scope and outstanding tolerance to various functional groups like hydroxyl and, of course, practical instance via the synthesis of doxepin and nordoxepin molecules.
View Article and Find Full Text PDFWe report the first asymmetric total synthesis of recently isolated heterodimeric alkaloids, narcipavlines A (1a) and B (1b), and narcikachnines A (2a) and B (2b), thereby confirming their absolute stereochemistry. These alkaloids showcase a unique heterodimeric structure, amalgamating two distinct types of alkaloids: the -hydrodibenzofuran containing tetracyclic galantamine core (6a) and the galanthindole core (7) featuring a biaryl axis. The presence of this biaryl axis, coupled with the substantial galantamine core (6a) at the substituents, imposes constraints on free rotation around the C-C axis, resulting in atropisomerism, an exceedingly rare phenomenon in nature.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of Chemical Engineering, State Key Laboratory Breeding Base of Green Chemical Synthesis Technology, Zhejiang University of Technology, Chaowang Road 18#, Hangzhou 310014, P. R. China.
Herein, a cobalt-catalyzed intramolecular enantioselective reductive Heck reaction is disclosed. Starting from --iodoaryl-2-(trifluoromethyl)acrylamides, a plethora of chiral oxindoles bearing trifluoromethylated quaternary stereogenic centers at the C3-position are achieved in moderate to good yields (up to 88% yield) and good to excellent enantioselectivities (up to 94% ee) by employing zinc/silane as reducing agent. Other than the trifluoromethyl group, a number of chiral oxindoles bearing alkyl, aryl, and ester groups at C3-position were also obtained albeit in relatively lower enantioselectivities (68-78% ee).
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