An Electrocatalytic Approach to the Radical Difunctionalization of Alkenes

ACS Catalysis, Год журнала: 2018, Номер 8(6), С. 5175 - 5187

Опубликована: Апрель 26, 2018

Given its many distinct characteristics, electrochemistry represents an attractive approach to meet the prevailing trends in organic synthesis. In particular, electrocatalysis—a process that integrates and small-molecule catalysis—has potential substantially improve scope of synthetic provide a wide range useful transformations. Recently, we have demonstrated new catalytic approaches combine redox-metal catalysis for oxidative difunctionalization alkenes access diverse array vicinally functionalized structures. This Perspective details our design principles underpinning development electrochemical diazidation, dichlorination, halotrifluoromethylation alkenes, which were built on foundational work by others areas electrochemistry, radical chemistry, transition-metal catalysis. The introduction redox-active Mn catalysts allows generation intermediates from readily available reagents at low potentials under mild conditions. These transition metals also impart selectivity control over alkene functionalization processes functioning as group transfer agents. As such, electrocatalytic reactions exhibit excellent chemoselectivity, broad substrate scope, high functional compatibility. Specifically, anodically coupled electrolysis, pairs two single-electron oxidation events parallel manner, enables regio- chemoselective heterodifunctionalization alkenes. products transformations describe this represent pertinent structures numerous medicinally relevant compounds. We anticipate parameters presented here are general will platform systems other challenging redox

Язык: Английский

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HFIP in Organic Synthesis

Chemical Reviews, Год журнала: 2022, Номер 122(15), С. 12544 - 12747

Опубликована: Июль 17, 2022

1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) is a polar, strongly hydrogen bond-donating solvent that has found numerous uses in organic synthesis due to its ability stabilize ionic species, transfer protons, and engage range of other intermolecular interactions. The use this exponentially increased the past decade become choice some areas, such as C–H functionalization chemistry. In review, following brief history HFIP an overview physical properties, literature examples reactions using or additive are presented, emphasizing effect each reaction.

Язык: Английский

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Enantioselective Synthesis of Cyclobutenes by Intermolecular [2+2] Cycloaddition with Non-C₂ Symmetric Digold Catalysts

Journal of the American Chemical Society, Год журнала: 2017, Номер 139(39), С. 13628 - 13631

Опубликована: Сен. 19, 2017

The enantioselective intermolecular gold(I)-catalyzed [2+2] cycloaddition of terminal alkynes and alkenes has been achieved using non-C

Язык: Английский

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Oxoammonium salts are catalysing efficient and selective halogenation of olefins, alkynes and aromatics

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Июнь 23, 2021

Abstract Electrophilic halogenation reactions have been a reliable approach to accessing organohalides. During the past decades, various catalytic systems developed for activation of haleniums. However, there is still short effective catalysts, which could cover and broad scope unsaturated compounds. Herein, TEMPO (2,2,6,6-tetramethylpiperidine nitroxide) its derivatives are disclosed as active catalysts electrophilic olefins, alkynes, aromatics. These stable, readily available, reactive enough activate haleniums including Br + , I even Cl reagents. This system applicable halogenations haloarylation olefins or dibromination were rarely realized in previous Lewis base catalysis acid catalysis. The high ability attributed synergistic model halogenating reagents, where carbonyl group halogen atom both activated by present

Язык: Английский

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Access to Alkyl-Substituted Lactone via Photoredox-Catalyzed Alkylation/Lactonization of Unsaturated Carboxylic Acids

Organic Letters, Год журнала: 2017, Номер 19(21), С. 5900 - 5903

Опубликована: Окт. 17, 2017

An efficient photoredox-catalyzed alkylation/lactonization reaction of unsaturated carboxylic acids by using alkyl N-hydroxyphthalimide esters as alkylation reagents has been developed. Varieties redox-active derived from aliphatic were proved viable in this method, affording substituted lactones moderate to good yields. This redox-neutral procedure features mild conditions and operational simplicity, which provides a new strategy for the synthesis lactones.

Язык: Английский

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Asymmetric Catalytic Halofunctionalization of α,β-Unsaturated Carbonyl Compounds

The Journal of Organic Chemistry, Год журнала: 2018, Номер 84(1), С. 1 - 13

Опубликована: Окт. 19, 2018

Halofunctionalization methods enable the vicinal difunctionalization of alkenes with heteroatom nucleophiles and halogen moieties. As a fundamental transformation in organic synthesis, catalytic asymmetric variants have only recently been reported. In sharp contrast to halocyclization simple which involves nucleophile-assisted alkene activation process, halofunctionalization enones developed by our laboratory features an electrophile-assisted 1,4-addition pathway. Our work this area has resulted development several different types regio-, diastereo-, enantioselective processes, including inter- intramolecular haloaminations, haloetherifications, haloazidations. The scope, updated mechanism, limitations, future perspective these reactions are discussed.

Язык: Английский

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Chiral Sulfide Catalysis for Desymmetrizing Enantioselective Chlorination

Angewandte Chemie International Edition, Год журнала: 2018, Номер 58(5), С. 1315 - 1319

Опубликована: Ноя. 20, 2018

Abstract An unprecendented chiral sulfide catalyzed desymmetrizing enantioselective chlorination is disclosed. Various aryl‐tethered diolefins and diaryl‐tethered olefins afforded teralins tricyclic hexahydrophenalene derivatives, respectively, bearing multiple stereogenic centers in high yields with excellent enantio‐ diastereoselectivities. In contrast, the tertiary amine catalyst (DHQD) 2 PHAL led to a diastereomeric product. The products could be transformed into variety of compounds, such as spiro‐N‐heterocycles.

Язык: Английский

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Hexafluoroisopropanol‐Promoted Haloamidation and Halolactonization of Unactivated Alkenes

Angewandte Chemie International Edition, Год журнала: 2020, Номер 60(2), С. 946 - 953

Опубликована: Сен. 21, 2020

Pyrrolidine and piperidine derivatives bearing halide functional groups are prevalent building blocks in drug discovery as halides can serve an anchor for post-modifications. In principle, one of the simplest ways to build these frameworks is haloamination alkenes. While progress has been made this field, notably with development enantioselective versions, reaction still fraught limitations terms reactivity. Besides, a major question remaining understand mechanism at work. The formation haliranium intermediate typically mentioned, but limited mechanistic evidence supports it. Reported here efficient metal- oxidant-free protocol achieve haloamidation olefins, promoted by hexafluoroisopropanol, along DFT investigation mechanism. These findings should guide future more complex transformations field halofunctionalization.

Язык: Английский

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Flavin-dependent halogenases catalyze enantioselective olefin halocyclization

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Июнь 1, 2021

Abstract Halocyclization of alkenes is a powerful bond-forming tool in synthetic organic chemistry and key step natural product biosynthesis, but catalyzing halocyclization with high enantioselectivity remains challenging task. Identifying suitable enzymes that catalyze enantioselective simple olefins would therefore have significant value. Flavin-dependent halogenases (FDHs) halogenation arene enol(ate) substrates. Herein, we reveal FDHs engineered to site-selective aromatic also non-native bromolactonization near-native catalytic proficiency. Highly selective achieved by characterizing mitigating the release HOBr from FDH active site using combination reaction optimization protein engineering. The structural origins improvements imparted mutations responsible for emergence halocyclase activity are discussed. This expansion presages development wide range biocatalytic reactions.

Язык: Английский

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Organoselenium-catalyzed enantioselective syn-dichlorination of unbiased alkenes

Tetrahedron, Год журнала: 2019, Номер 75(31), С. 4086 - 4098

Опубликована: Июнь 1, 2019

Язык: Английский

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