Copper-catalyzed intermolecular C(sp<sup>3</sup>)–H bond functionalization towards the synthesis of tertiary carbamates

Chikkade, Prasanna Kumara; Kuninobu, Yoichiro; Kanai, Motomu

doi:10.1039/c5sc00238a

Cited by 45 publications

(17 citation statements)

References 48 publications

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“…[292] Calculations supported the suggested combination of the alkyl radical with the amine ligand, which is referred to as "radical capture"a nd can be considered as aformal homolytic substitution at nitrogen. [290] Based on this seminal work, other radical Cu-catalyzed CÀN bond formations at activated CÀHs ites with amides,s ulfonamides,i mides, [293] carbamates, [294] sulfoximines, [295] and Weinreb amides [296] as the nucleophilic Nsources have been developed. Recently,c arboxylic acids in combination with alkyl chlorides [297] and hypervalent iodine [298] were established in such couplings.M oreover,s uch aminations can be combined with ar adical addition to aC =Cd ouble bond where uncatalyzed radical C À Cb ond formation precedes the Cucatalyzed C À Nbond formation.…”

Section: Coppermentioning

confidence: 99%

The Persistent Radical Effect in Organic Synthesis

2019

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Radical–radical couplings are mostly nearly diffusion‐controlled processes. Therefore, the selective cross‐coupling of two different radicals is challenging and not a synthetically valuable transformation. However, if the radicals have different lifetimes and if they are generated at equal rates, cross‐coupling will become the dominant process. This high cross‐selectivity is based on a kinetic phenomenon called the persistent radical effect (PRE). In this Review, an explanation of the PRE supported by simulations of simple model systems is provided. Radical stabilities are discussed within the context of their lifetimes, and various examples of PRE‐mediated radical–radical couplings in synthesis are summarized. It is shown that the PRE is not restricted to the coupling of a persistent with a transient radical. If one coupling partner is longer‐lived than the other transient radical, the PRE operates and high cross‐selectivity is achieved. This important point expands the scope of PRE‐mediated radical chemistry. The Review is divided into two parts, namely 1) the coupling of persistent or longer‐lived organic radicals and 2) “radical–metal crossover reactions”; here, metal‐centered radical species and more generally longer‐lived transition‐metal complexes that are able to react with radicals are discussed—a field that has flourished recently.

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Section: Coppermentioning

confidence: 99%

The Persistent Radical Effect in Organic Synthesis

2019

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“…Eventually, 132i released Cu (OTf)2 and acquired the relating result 132 to finish the catalytic cycle (Scheme-XXXV). Cu Scheme-XXXV: A copper-catalyzed C-H/N-H radical/radical cross coupling for the synthesis of allylic amine A copper mediated intermolecular C-H bond functionalization between un-activated alkanes 133 and isocyanates 134 was outlined by Kanai and co-workers [59], which could supplied the tertiary carbamates (136-143) specifically, catalyzed by abundantly accessible first-period of transition metal complexes with ( t BuO) 2 as the oxidant 135. A suggested mechanism including a Cu(I)-Cu(II)-Cu(III) redox catalytic cycle is outlined by the authors (Scheme-XXXVI).…”

Section: Ncmentioning

confidence: 99%

Recent Free-Radical Reactions

Khalid¹,

Mohammed²

2018

Asian J. Chem.

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Free radical reactions are one of the most coveted simulated objectives has been increasingly popular, very versatile and very important method in organic synthesis and due to their considerable and precious applications in different fields are widely used in the past few years. Free radical reactions can be efficient in the preparation of a large number of organic compounds which has been found large applications in many areas of life due to the ease of use of this method, accuracy, selectivity and required mild condition. Free radical reactions have many types of reaction e.g., cyclization, decarboxylation, additions reactions, hydrogen atom abstractions and alkynylation etc. [1a]. Free radicals are very supportive for the synthesis of cycles, atomic relocating permit effective groups to combine and facilely used to generate a number of ligations in one step [1b]. Likewise, the improvement of radicalmediated, C-C bond-forming transmutation has also attracted increasing attention. Usually, these protocols tolerate good selectivity, are highly convenient with collective functional This review highlights the most recent syntheses of free radical reactions, which included numerous processes (photoredox catalysis freeradical reactions, free-radical cascade processes reactions, Minisci-type free radical alkylation reactions and metal-catalysis free radical reactions). A photoredox-catalyzed C-H functioning of aromatic heterocyclic utilizing an assortment of various, alkyltrifluoroborates has been mentioned. Utilizing organo-photocatalyst and a moderate oxidant, conditions malleable for functionalizing complex aromatic heterocyclics are outlined to prepare a oriental agent for late-stage derivatization. Radical alkylations of aromatic heterocyclic (Minisci reactions) appear a more direct functionalization of particular, C-H bonds. For the ground mentioned above, alkylation designing using radical have recently risen to significance for the late-stage functionalization of aromatic heterocyclic framework. Therefore, this issue is the primary point of the present survey, which thinks about work from the most recent five years. The work is ordered by the key procedures associated with the synthesis of free-radical reactions, planning to give researchers a simple comprehension of this free radical-reactions-based science and to give bits of knowledge to provide insights for further investigations.

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“…25 This type of Cu-catalyzed-t-BuOOt-Bu-mediated aliphatic C-H oxidation strategy could be further applied for synthesis of tertiary carbamates using isocyanates as the amide source (Scheme 17). 26 The reaction of Cu(I) species with t-BuOOt-Bu and isocyanate generates Cu(II)-amide complex 19, which is coupled with the C-radical derived from alkanes via H-radical abstraction by the transient t-butoxy radical, affording tertiary carbamates.…”

Section: With Di-t-butylperoxide (T-buoot-bu)mentioning

confidence: 99%