Recent progress in cathodic reduction-enabled organic electrosynthesis: Trends, challenges, and opportunities

eScience, Journal Year: 2022, Volume and Issue: 2(3), P. 243 - 277

Published: April 23, 2022

Compared with general redox chemistry, electrochemistry using the electron as a potent, controllable, yet traceless alternative to chemical oxidants/reductants usually offers more sustainable options for achieving selective organic synthesis. With its environmentally benign features gradually being uncovered and studied, electrosynthesis is currently undergoing revival becoming rapidly growing area within synthetic community. Among electrochemical transformations, anodically enabled ones have been far extensively exploited than those driven by cathodic reduction, although both approaches are conceptually attractive. To stimulate development of cathodically reactions, this review summarizes recently developed reductive electrosynthetic protocols, discussing highlighting reaction features, substrate scopes, applications, plausible mechanisms reveal recent trends in area. Herein, reduction-enabled preparative transformations categorized into four types: reduction (1) unsaturated hydrocarbons, (2) heteroatom-containing carbon-based systems, (3) saturated C-hetero or C–C polar/strained bonds, (4) hetero-hetero linkages. Apart from net electroreductive few examples photo-electrosynthesis well paired electrolysis also introduced, which offer opportunities overcome certain limitations improve versatility. The electrochemically driven, transition metal-catalyzed cross-couplings that comprehensively discussed several other reviews not included here.

Language: Английский

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Controlling Ni redox states by dynamic ligand exchange for electroreductive Csp3–Csp2 coupling

Science, Journal Year: 2022, Volume and Issue: 376(6591), P. 410 - 416

Published: April 21, 2022

Cross-electrophile coupling (XEC) reactions of aryl and alkyl electrophiles are appealing but limited to specific substrate classes. Here, we report electroreductive XEC previously incompatible including tertiary bromides, chlorides, aryl/vinyl triflates. Reactions rely on the merger an electrochemically active complex that selectively reacts with bromides through 1e

Language: Английский

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Oxidative Addition of Aryl Halides to a Ni(I)-Bipyridine Complex

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(12), P. 5575 - 5582

Published: March 17, 2022

The oxidative addition of aryl halides to bipyridine- or phenanthroline-ligated nickel(I) is a commonly proposed step in nickel catalysis. However, there scarcity complexes this type that both are well-defined and undergo with halides, hampering organometallic studies process. We report the synthesis Ni(I) complex, [(CO2Etbpy)NiICl]4 (1). Its solution-phase speciation characterized by significant population monomer redox equilibrium can be perturbed π-acceptors σ-donors. 1 reacts readily bromides, mechanistic consistent pathway proceeding through an initial → Ni(III) form species. Such process was demonstrated stoichiometrically for first time, affording structurally complex.

Language: Английский

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Electrochemical Enantioselective Nucleophilic α-C(sp³)–H Alkenylation of 2-Acyl Imidazoles

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(15), P. 6964 - 6971

Published: April 6, 2022

Merging electrochemistry with asymmetric catalysis promises to provide an environmentally friendly and efficient strategy for the construction of nonracemic chiral molecules. However, in practice, significant challenges arise from instability or incompatibility catalysts under electrochemical conditions at interface electrode solution. Herein, we report a catalytic indirect electrolysis employing combination redox mediator chiral-at-rhodium Lewis acid, which achieves previously elusive enantioselective nucleophilic α-C(sp3)−H alkenylation ketones. Specifically, 2-acyl imidazoles react potassium alkenyl trifluoroborates high yields (up 94%) exceptional enantioselectivities (27 examples ≥99% ee) without need any additional stoichiometric oxidants (overall 40 examples). The new electrosynthesis can be scaled gram quantities was applied straightforward synthesis intermediates natural product cryptophycin A cathepsin K inhibitor.

Language: Английский

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Recent advances in the electrochemical generation of 1,3-dicarbonyl radicals from C–H bonds

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(11), P. 2830 - 2848

Published: Jan. 1, 2023

Recent advances in the electrochemical generation of 1,3-dicarbonyl radicals from C–H bonds and their mechanistic insights synthetic applications have been summarized.

Language: Английский

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Cu-Electrocatalytic Diazidation of Alkenes at ppm Catalyst Loading

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(27), P. 11980 - 11985

Published: June 30, 2022

The 1,2-diamine motif is prevalent in natural products, small-molecule pharmaceuticals, and catalysts for asymmetric synthesis. Transition metal catalyzed alkene diazidation has evolved to be an attractive strategy access vicinal primary diamines but remains challenging, especially practical applications, due the restriction a certain type of olefins, frequent use chemical oxidants, requirement high loadings (1 mol % or above). Herein we report scalable Cu-electrocatalytic reaction with 0.02 (200 ppm) copper(II) acetylacetonate as precatalyst without exogenous ligands. In addition its low catalyst loading, electrocatalytic method scalable, compatible broad range functional groups, applicable α,β-unsaturated carbonyl compounds mono-, di-, tri-, tetrasubstituted unactivated alkenes.

Language: Английский

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Counter Electrode Reactions—Important Stumbling Blocks on the Way to a Working Electro‐organic Synthesis

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(47)

Published: June 7, 2022

Over the past two decades, electro-organic synthesis has gained significant interest, both in technical and academic research as well terms of applications. The omission stoichiometric oxidizers or reducing agents enables a more sustainable route for redox reactions organic chemistry. Even if it is well-known that every electrochemical oxidation only viable with an associated reduction reaction vice versa, relevance counter often less addressed. In this Review, importance corresponding highlighted how can affect performance selectivity electrolytic conversion. A selection common strategies unique concepts to tackle issue are surveyed provide guide select appropriate synthesis.

Language: Английский

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Recent advances in transition metal-mediated trifluoromethylation reactions

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(75), P. 10442 - 10468

Published: Jan. 1, 2022

Fluorine compounds are known for their abundance in more than 20% of pharmaceutical and agrochemical products mainly due to the enhanced lipophilicity, metabolic stability pharmacokinetic properties organofluorides. Consequently, last decade has seen enormous growth incorporation a trifluoromethyl group into organic motifs. With significance, this review aims provide complete picture transition metal-mediated construction C(sp3, sp2, sp)-CF3 bonds via C-H/X bond functionalization or addition processes both aliphatic aromatic hydrocarbons. Diversified reagents ranging from radical electrophilic nucleophilic trifluoromethylating agents respective mechanisms have been further deliberated comprehensive overview. The coverage on topic is expected make unique beneficial future applications enriching community towards improvements field trifluoromethylation reactions, turn improving propensity development drugs.

Language: Английский

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A guide to organic electroreduction using sacrificial anodes

Chemical Society Reviews, Journal Year: 2023, Volume and Issue: 52(4), P. 1168 - 1188

Published: Jan. 1, 2023

This review focuses on recent advances in sacrificial anode-enabled organic electroreductions.

Language: Английский

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Electroreductive Dicarboxylation of Unactivated Skipped Dienes with CO₂

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(23)

Published: April 3, 2023

Carboxylation of easily available alkenes with CO2 is highly important to afford value-added carboxylic acids. Although dicarboxylation activated alkenes, especially 1,3-dienes, has been widely investigated, the challenging unactivated 1,n-dienes (n>3) remains unexplored. Herein, we report first skipped dienes via electrochemistry, affording valuable dicarboxylic Control experiments and DFT calculations support single electron transfer (SET) reduction its radical anion, which followed by sluggish addition SET unstabilized alkyl radicals carbanions nucleophilic attack on give desired products. This reaction features mild conditions, broad substrate scope, facile derivations products promising application in polymer chemistry.

Language: Английский

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