Atom‐Transfer Radical Addition to Unactivated Alkenes by using Heterogeneous Visible‐Light Photocatalysis

Mao, Liang-Liang; Cong, Huan

doi:10.1002/cssc.201701382

Cited by 27 publications

(11 citation statements)

References 67 publications

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“…An intermolecular radical addition‐cyclization sequence with a perfluoroalkyl iodide 2 s was employed to convert 20 to the cyclopentane 21 in 94% yield ( cis / trans ∼80:20). The observed diastereoselectivity matches expectations for such a radical process [77] and the yield compares well with reported procedures [77–79] including the ones requiring photoredox catalysis [80–82] …”

Section: Resultssupporting

confidence: 81%

“…The use of transition metal catalysis (Fe, Cu, Ru, Ni for instance) is also a popular way of initiating (and often catalyzing) ATRA processes, [22–28] 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 [29–37] . Despite all these studies, the need of a simple and broadly applicable method to run ATRA reactions remains highly needed.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, visible light-promoted electron transfers (strategy C) have been reported in the presence of diverse, often expensive, transition metal catalysts. [29][30][31][32][33][34][35][36][37] Despite all these studies, the need of a simple and broadly applicable method to run ATRA reactions remains highly needed. Ideally, the reaction should work with a wide range of reactive -and less reactive -substrates and reagents under mild reaction conditions that avoid the use of expensive or toxic metals and the formation of byproducts which are difficult to remove.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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).

show abstract

Section: Resultssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Methyl Radical Initiated Kharasch and Related Reactions

Tappin

Renaud

2020

Adv Synth Catal

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“…90 Cong and Mao combined a TiO 2 semiconductor with hypervalent iodineĲIII) reagents, such as Togni I or PIDA ((diacetoxyiodo)benzene), as co-initiators to drive the ATRA reaction using visible light irradiation (blue LED). 91 The reaction system worked smoothly using alkyl halides containing different functional groups and unactivated olefins (up to 95% in yields). Also, a more challenging ATRA donor could be used under the optimized conditions: chloroform was used as both alkyl halide partner and solvent leading to the corresponding hydrotrichloromethylation product with good yield (62%).…”

Section: View Article Onlinementioning

confidence: 99%

Application of metal oxide semiconductors in light-driven organic transformations

Paiva

Noël

2019

Catal. Sci. Technol.

164

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The search for greener alternatives to perform organic reactions has become the order of the day in the chemistry community. In this regard, the use of heterogeneous photocatalysts has emerged as a powerful alternative to replace transition metal-based complexes and organic dyes to enable light-driven organic transformations. Within this realm, metal oxide semiconductors (MOS) have become increasingly popular due to their recyclability, availability, energy efficiency, photo-and chemical stability and generally low toxicity. Here, we cover the most relevant literature related to the use of MOS as photocatalysts to light induce organic reactions, including oxidations, C-C and C-heteroatom bond formations. We also discuss the mechanisms involved in these processes, as well as the hitherto best known MOS modifications able to enhance their photocatalytic performance.

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“…More recently, visible lightpromoted electron transfers (strategy C) have been reported in the presence of diverse, often expensive, transition metal catalysts. [28][29][30][31][32][33][34][35][36] Despite all these studies, the need of a simple and broadly applicable method to run ATRA reactions remains highly needed. Ideally, the reaction should work with a wide range of reactive-and less reactive-substrates and reagents under mild reaction conditions that avoid the use of expensive or toxic metals and the formation of byproducts which are difficult to remove.…”

Section: Introductionmentioning

confidence: 99%

Methyl Radical Initiated Kharasch and Related Reactions

Tappin¹,

Renaud²

2020

Preprint

View full text Add to dashboard Cite

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 (2.0 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 byproducts (CO2).

show abstract

Atom‐Transfer Radical Addition to Unactivated Alkenes by using Heterogeneous Visible‐Light Photocatalysis

Cited by 27 publications

References 67 publications

Methyl Radical Initiated Kharasch and Related Reactions

Methyl Radical Initiated Kharasch and Related Reactions

Application of metal oxide semiconductors in light-driven organic transformations

Methyl Radical Initiated Kharasch and Related Reactions

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