Ruthenium-catalyzed Atom Transfer Radical Addition Reactions

Severin, Kay

doi:10.2533/chimia.2012.386

Cited by 39 publications

(14 citation statements)

References 14 publications

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“…ATRC is the intramolecular version of ATRA and is attractive synthetically because the halogen (X) is retained, which allows post‐cyclization functionalization if required 3c,6,7. Copper6 and ruthenium catalysts3g,8a–8c are most commonly employed, although iron,9 palladium10 and iridium11 have also been investigated.…”

Section: Introductionmentioning

confidence: 99%

Copper Catalyzed Atom Transfer Radical Cyclization Reactions

Clark

2016

Eur J Org Chem

137

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Atom transfer radical cyclization (ATRC) is a powerful technique to prepare functionalized 4–10 membered ring systems using transition metal catalysts. In this review recent advances in the use of copper complexes are described. In particular the effect of different ligands on reactivity, selectivity and product outcome are illustrated with application to heterocycle and natural product synthesis. New approaches that increase catalyst efficiency with supplemental reducing agents are reviewed and examples using green solvents, benign reducing agents (e.g. ascorbic acid) and with catalyst loadings as low as 0.05 mol‐% are highlighted. Radical addition to aromatic rings and rearrangement reactions under ATRC conditions as well as application to radical‐polar crossover reactions are also described.

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Section: Introductionmentioning

confidence: 99%

Copper Catalyzed Atom Transfer Radical Cyclization Reactions

Clark

2016

Eur J Org Chem

137

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“…A simple, mild and generally applicable procedure for halogen ATRA and related reactions has been developed. This procedure is suitable to run non‐catalyzed ATRA favored by thermodynamic and polar effects and is not intended to run challenging ATRA that require a catalyst involved in the reaction chain process to overcome kinetically or thermodynamically difficult steps [22–28] . The use of DTBHN (or DTBPO) allows efficient initiation involving atom/group transfer processes, mediated by methyl radicals, at moderate temperature.…”

Section: Resultsmentioning

confidence: 99%

“…This procedure is suitable to run non-catalyzed ATRA favored by thermodynamic and polar effects and is not intended to run challenging ATRA that require a catalyst involved in the reaction chain process to overcome kinetically or thermodynamically difficult steps. [22][23][24][25][26][27][28] The use of DTBHN (or DTBPO) allows efficient initiation involving atom/group transfer processes, mediated by methyl radicals, at moderate temperature. The main advantage of this approach is the absence of product contamination caused by the initiation thus greatly facilitating product purification.…”

Section: Resultsmentioning

confidence: 99%

“…[17][18][19] However the pyrophoric character of triethylborane, and inherent incompatibility with α-halo-and α-chalcoketones, [20,21] have made this strategy less attractive. The use of transition metal catalysis (Fe, Cu, Ru, Ni for instance) is also a popular way of initiating (and often catalyzing) ATRA processes, [22][23][24][25][26][27][28] this approach involves an initial inner-sphere electron transfer (strategy C) and is particularly suitable for reactions onto activated alkenes such as styrene derivatives. More recently, visible light-promoted electron transfers (strategy C) have been reported in the presence of diverse, often expensive, transition metal catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Methyl Radical Initiated Kharasch and Related Reactions

Tappin

Renaud

2020

Adv Synth Catal

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An improved procedure to run halogen atom and related chalcogen group transfer radical additions is reported. The procedure relies on the thermal decomposition of di‐tert‐butylhyponitrite (DTBHN), a safer alternative to the explosive diacetyl peroxide, to produce highly reactive methyl radicals that can initiate the chain process. This mode of initiation generates byproducts that are either gaseous (N2) or volatile (acetone and methyl halide) thereby facilitating greatly product purification by either flash column chromatography or distillation. In addition, remarkably simple and mild reaction conditions (refluxing EtOAc during 30 minutes under normal atmosphere) and a low excess of the radical precursor reagent (2 equivalents) make this protocol particularly attractive for preparative synthetic applications. This initiation procedure has been demonstrated with a broad scope since it works efficiently to add a range of electrophilic radicals generated from iodides, bromides, selenides and xanthates over a range of unactivated terminal alkenes. A diverse set of radical trap substrates exemplifies a broad functional group tolerance. Finally, di‐tert‐butyl peroxyoxalate (DTBPO) is also demonstrated as alternative source of tert‐butoxyl radicals to initiate these reactions under identical conditions which gives gaseous by‐products (CO2).

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“…Atom transfer radical addition (ATRA) of haloalkanes to unsaturated compounds serves as a simple and useful method to form C-C and C-X bonds. Many successful ATRA reactions have been reported in literature, most of which are metal-catalyzed, employing copper-, ruthenium-, iridium-, palladium-, or nickel-based complexes [13,14,15,16,17,18]. Along the same lines, Bach, Nicewicz and Melchiorre emphasized the ease of controlling photogenerated radicals, opening new avenues in the field of photocatalysis [19,20,21].…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Atom Transfer Radical Addition to Olefins Utilizing Novel Photocatalysts

et al. 2019

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Photocatalysis is a rapidly evolving area of research in modern organic synthesis. Among the traditional photocatalysts, metal-complexes based on ruthenium or iridium are the most common. Herein, we present the synthesis of two photoactive, ruthenium-based complexes bearing pyridine-quinoline or terpyridine ligands with extended aromatic conjugation. Our complexes were utilized in the atom transfer radical addition (ATRA) of haloalkanes to olefins, using bromoacetonitrile or bromotrichloromethane as the source of the alkyl group. The tailor-made ruthenium-based catalyst bearing the pyridine-quinoline bidentate ligand proved to be the best-performing photocatalyst, among a range of metal complexes and organocatalysts, efficiently catalyzing both reactions. These photocatalytic atom transfer protocols can be expanded into a broad scope of olefins. In both protocols, the photocatalytic reactions led to products in good to excellent isolated yields.

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Ruthenium-catalyzed Atom Transfer Radical Addition Reactions

Cited by 39 publications

References 14 publications

Copper Catalyzed Atom Transfer Radical Cyclization Reactions

Copper Catalyzed Atom Transfer Radical Cyclization Reactions

Methyl Radical Initiated Kharasch and Related Reactions

Photocatalytic Atom Transfer Radical Addition to Olefins Utilizing Novel Photocatalysts

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