Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

Chemical Reviews, Journal Year: 2017, Volume and Issue: 117(23), P. 13810 - 13889

Published: Nov. 1, 2017

Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals area is expanding scope coupling partners. In past decade, diazo compounds (or their precursors N-tosylhydrazones) emerged nucleophilic partners C-C single bond or C═C double formations transition-metal-catalyzed reactions. This type reaction involves following general steps. First, organometallic species generated by various processes, including oxidative addition, transmetalation, cyclization, cleavage, and C-H activation. Subsequently, reacts with substrate to generate metal carbene intermediate, which undergoes rapid migratory insertion form a bond. The new from may undergo transformations. carbene-based has proven be general: transition metals Pd, Cu, Rh, Ni, Co, Ir are effective catalysts; also extended substrates other than compounds; cascade processes devised based on insertion. review will summarize achievements made this field since 2001.

Language: Английский

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Transition metal-catalyzed C–H functionalization of N-oxyenamine internal oxidants

Chemical Society Reviews, Journal Year: 2014, Volume and Issue: 44(5), P. 1155 - 1171

Published: Nov. 24, 2014

The N-oxyenamine internal oxidant gives more chance to investigate the C–H bond activation under mild reaction conditions.

Language: Английский

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Metal‐Catalyzed Annulations through Activation and Cleavage of C−H Bonds

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(37), P. 11000 - 11019

Published: June 22, 2016

The exponential increase in the number of catalytic transformations that involve a metal-promoted activation hitherto considered inert C-H bonds is promoting fundamental change field synthetic chemistry. Although most reactions involving activations consist simple functionalizations or additions, recent years have witnessed an upsurge related can be formally as cycloaddition processes. These are particularly appealing from perspective because they allow conversion readily available substrates into highly valuable cyclic products rapid and sustainable manner. In many cases, these annulations formation metallacyclic intermediates resemble those proposed for standard metal-catalyzed cycloadditions unsaturated precursors.

Language: Английский

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Transition metal-catalysed couplings between arenes and strained or reactive rings: combination of C–H activation and ring scission

Chemical Society Reviews, Journal Year: 2016, Volume and Issue: 45(23), P. 6462 - 6477

Published: Jan. 1, 2016

Transition metal-catalysed systems of C–H activation arenes in combination with opening strained or reactive three, four, and five membered rings are summarized this review.

Language: Английский

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Rhodium-Catalyzed C–H Activation of Phenacyl Ammonium Salts Assisted by an Oxidizing C–N Bond: A Combination of Experimental and Theoretical Studies

Journal of the American Chemical Society, Journal Year: 2015, Volume and Issue: 137(4), P. 1623 - 1631

Published: Jan. 8, 2015

Rh(III)-catalyzed C–H activation assisted by an oxidizing directing group has evolved to a mild and redox-economic strategy for the construction of heterocycles. Despite success, these coupling systems are currently limited cleavage N–O or N–N bond. Cleavage C–N bond, which allows complementary carbocycle synthesis, is unprecedented. In this article, α-ammonium acetophenones with bond have been designed as substrates under redox-neutral conditions. The α-diazo esters afforded benzocyclopentanones, unactivated alkenes such styrenes aliphatic olefins gave ortho-olefinated acetophenoes. both reactions proceeded broad scope, high efficiency, functional tolerance. Moreover, efficient one-pot diazo realized starting from α-bromoacetophenones triethylamine. reaction mechanism studied combination experimental theoretical methods. particular, three distinct mechanistic pathways scrutinized DFT studies, revealed that occurs via C-bound enolate-assisted concerted metalation–deprotonation rate-limiting. subsequent C–C formation steps, lowest energy pathway involves two rhodium carbene species key intermediates.

Language: Английский

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New Approaches to the Synthesis of Metal Carbenes

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(32), P. 9134 - 9166

Published: June 16, 2016

Abstract Metal carbenes usually possess versatile reactivities that are controlled by the presence of both metals and ligands. Diazo compounds commonly used for generation such species through elimination nitrogen. However, they often unstable, explosive, toxic, which limits their applications in large‐scale syntheses. Thus, identifying sustainable safe surrogates metal has attracted great attention. In this Review, we summarize some most important breakthroughs generation, catalytic reactions, selectivity control from non‐diazo starting compounds.

Language: Английский

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Cross‐Coupling of α‐Carbonyl Sulfoxonium Ylides with C−H Bonds

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(42), P. 13117 - 13121

Published: Aug. 29, 2017

Abstract The functionalization of carbon–hydrogen bonds in non‐nucleophilic substrates using α‐carbonyl sulfoxonium ylides has not been so far investigated, despite the potential safety advantages that such reagents would provide over either diazo compounds or their situ precursors. Described herein are cross‐coupling reactions with C(sp 2 )−H arenes and heteroarenes presence a rhodium catalyst. reaction proceeds by succession C−H activation, migratory insertion ylide into carbon–metal bond, protodemetalation, last step being turnover‐limiting. method is applied to synthesis benz[c]acridines when allied an iridium‐catalyzed dehydrative cyclization.

Language: Английский

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C–H bond functionalization based on metal carbene migratory insertion

Chemical Communications, Journal Year: 2015, Volume and Issue: 51(38), P. 7986 - 7995

Published: Jan. 1, 2015

C–H bond activation has been merged with carbene coupling to furnish a series of novel synthetic methodologies.

Language: Английский

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Cationic Cobalt(III) Catalyzed Indole Synthesis: The Regioselective Intermolecular Cyclization of N‐Nitrosoanilines and Alkynes

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(12), P. 4035 - 4039

Published: Feb. 17, 2016

Abstract The unique regioselectivity and reactivity of cobalt(III) in the direct cyclization N‐nitrosoanilines with alkynes for expedient synthesis N‐substituted indoles is demonstrated. In presence a catalyst, high was observed when using unsymmetrical meta ‐substituted N‐nitrosoanilines. Moreover, internal bearing electron‐deficient groups, which are almost unreactive [Cp*Rh III ]‐catalyzed system, display good this transformation.

Language: Английский

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Sulfoxonium Ylides as a Carbene Precursor in Rh(III)-Catalyzed C–H Acylmethylation of Arenes

Organic Letters, Journal Year: 2017, Volume and Issue: 19(19), P. 5256 - 5259

Published: Sept. 13, 2017

Sulfoxonium ylides act as an efficient carbene precursor in rhodium(III)-catalyzed C-H acylmethlyation of a variety arenes assisted by different chelating groups, and both aryl- alkyl-substituted β-carbonyl sulfoxonium are applicable. The system proceeded under redox-neutral conditions with broad scope, high efficiency, functional group tolerance.

Language: Английский

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