Generation and cross-coupling of benzyl and phthalimide-N-oxyl radicals in a cerium(IV) ammonium nitrate/N-hydroxyphthalimide/ArCH2R system

Terent’ev, Alexander O.; Krylov, Igor B.; Sharipov, Mikhail Yu.; Kazanskaya, Zoya M.; Nikishin, G. I.

doi:10.1016/j.tet.2012.10.018

Cited by 49 publications

(32 citation statements)

References 71 publications

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“…Compounds 1a ‐ 4a , phthalimide (PI), DMF (“extra dry”), Bu 4 NClO 4 , and 1.5 М Bu 4 NOH aqueous solution were purchased from Acros Organics. Procedures for the synthesis and purification and the establishment of the structures of compounds 1 ‐ 11 were reported earlier . Compounds 12 , 13 , and 15 were synthesized by the reaction of NHPI with benzoyl chloride, acetyl chloride, and tosyl chloride, respectively.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical behavior of N‐oxyphthalimides: Cascades initiating self‐sustaining catalytic reductive N―O bond cleavage

Syroeshkin

Krylov

Hughes

et al. 2017

J of Physical Organic Chem

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N-oxyphthalimides are stable and easily accessible compounds that can produce oxygen radicals upon 1-electron reduction. We present a systematic study of electrochemical properties of N-oxyphthalimide derivatives (PI-ORs) in DMF by cyclic voltammetry. In all cases, electron transfer to the substrate leads to decomposition of the intermediate radical anion via the N-O bond cleavage. In the case of benzyloxyphthalimide or its derivatives containing electrondonating substituents, reductive electron transfer induces the chain decomposition of the substrate to phthalimide (PI) radical-anion and the corresponding carbonyl compound. The PI radical-anion product is a powerful reductant that can transfer an electron to the reactant PI-OR, thus establishing a catalytic cycle for reductive N-O scission. This self-catalytic process is reflected in a considerable decrease in the reduction current for the substrate (<1e -/molecule). By contrast, reductive fragmentations of benzyl derivatives containing electronwithdrawing substituents in the aromatic ring or at the benzylic position, as well as tosyl and alkyl derivatives, occur via a 1-electron mechanism. A sequence of N-O and C-C scissions was engineered to support the intermediacy of O-centered radicals in these processes.

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Section: Methodsmentioning

confidence: 99%

Electrochemical behavior of N‐oxyphthalimides: Cascades initiating self‐sustaining catalytic reductive N―O bond cleavage

Syroeshkin

Krylov

Hughes

et al. 2017

J of Physical Organic Chem

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“…The development of selective processes of C-H functionalization and oxidative coupling (cross-dehydrogenative coupling, CDC) is one of the most rapidly developing areas of modern organic chemistry. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] While cross-coupling reactions involving functional groups (-Hal, -B(OR) 2 , -SnR 3 , -ZnHal, MgHal, etc.) have already become classic methods for the formation of C-C and C-heteroatom bonds (heteroatom ¼ S, N, O, P), crossdehydrogenative coupling is a relatively new direction in the methodology of coupling, which meets such principles of green chemistry as atom-economy and step-economy.…”

Section: Introductionmentioning

confidence: 99%

“…3 CDC allows one to form the target chemical bond between molecules owing to selective cleavage of C-H and heteroatom-H bonds in the reagents without carrying out prefunctionalization. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] One of the most important problems in the realization of CDC is the selection of an oxidant that selectively cleaves certain C-H and heteroatom-H bonds. Stoichiometric or excess amounts of transition metal salts, [8][9][10][11][12] hypervalent iodine compounds [13][14][15][16][17] and DDQ 20,21 are oen used as oxidants.…”

Section: Introductionmentioning

confidence: 99%

Iminoxyl radicalsvs. tert-butylperoxyl radical in competitive oxidative C–O coupling with β-dicarbonyl compounds. Oxime ether formation prevails over Kharasch peroxidation

et al. 2018

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“…The oxidative C–O coupling of alkylarenes and related compounds 312 with N -hydroxyphthalimide ( 154b ) was performed using CuCl/PhI(OAc) 2 [ 252 ] or (NH 4 ) 2 Ce(NO 3 ) 6 [ 253 ] as the oxidizing agent ( Scheme 68 ). The reaction in the presence of the CuCl/PhI(OAc) 2 system gives somewhat higher yields of coupling products 313 compared with (NH 4 ) 2 Ce(NO 3 ) 6 , but it requires higher temperature, a longer reaction time, and relatively larger excesses of alkylarene.…”

Section: Reviewmentioning

confidence: 99%

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

Krylov

Vil

Terent’ev

2015

Beilstein J. Org. Chem.

171

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SummaryThe present review summarizes primary publications on the cross-dehydrogenative C–O coupling, with special emphasis on the studies published after 2000. The starting compound, which donates a carbon atom for the formation of a new C–O bond, is called the CH-reagent or the C-reagent, and the compound, an oxygen atom of which is involved in the new bond, is called the OH-reagent or the O-reagent. Alcohols and carboxylic acids are most commonly used as O-reagents; hydroxylamine derivatives, hydroperoxides, and sulfonic acids are employed less often. The cross-dehydrogenative C–O coupling reactions are carried out using different C-reagents, such as compounds containing directing functional groups (amide, heteroaromatic, oxime, and so on) and compounds with activated C–H bonds (aldehydes, alcohols, ketones, ethers, amines, amides, compounds containing the benzyl, allyl, or propargyl moiety). An analysis of the published data showed that the principles at the basis of a particular cross-dehydrogenative C–O coupling reaction are dictated mainly by the nature of the C-reagent. Hence, in the present review the data are classified according to the structures of C-reagents, and, in the second place, according to the type of oxidative systems. Besides the typical cross-dehydrogenative coupling reactions of CH- and OH-reagents, closely related C–H activation processes involving intermolecular C–O bond formation are discussed: acyloxylation reactions with ArI(O2CR)2 reagents and generation of O-reagents in situ from C-reagents (methylarenes, aldehydes, etc.).

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Generation and cross-coupling of benzyl and phthalimide-N-oxyl radicals in a cerium(IV) ammonium nitrate/N-hydroxyphthalimide/ArCH2R system

Cited by 49 publications

References 71 publications

Electrochemical behavior of N‐oxyphthalimides: Cascades initiating self‐sustaining catalytic reductive N―O bond cleavage

Electrochemical behavior of N‐oxyphthalimides: Cascades initiating self‐sustaining catalytic reductive N―O bond cleavage

Iminoxyl radicalsvs. tert-butylperoxyl radical in competitive oxidative C–O coupling with β-dicarbonyl compounds. Oxime ether formation prevails over Kharasch peroxidation

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

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