Catalyst-free and selective oxidation of pyridine derivatives and tertiary amines to corresponding N-oxides with 1,2-diphenyl-1,1,2,2-tetrahydroperoxyethane

Azarifar, Davood; Mahmoudi, Boshra

doi:10.1007/s13738-015-0776-8

Cited by 7 publications

(5 citation statements)

References 47 publications

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“…Importantly, pyridine and 2-methyl imidazole also remain intact under the reaction conditions (97 and 91% recovered, respectively). This is notable since these and similar heterocyclic substrates can form N-oxides in the presence of peroxide oxidants. , Overall, the intermolecular reaction screening predicts that the protocol should be applicable for the α-C–H cyanation of complex amine substrates.…”

Section: Resultsmentioning

confidence: 92%

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Iron-Catalyzed α-C–H Cyanation of Simple and Complex Tertiary Amines

2021

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This manuscript details the development of a general and mild protocol for the α-C-H cyanation of tertiary amines as well as its application in late stage functionalization. Suitable substrates include tertiary aliphatic, benzylic, and aniline-type substrates as well as complex substrates. Functional groups tolerated under the reaction conditions include various heterocycles, as well as ketones, amides, olefins, and alkynes. This broad substrate scope is remarkable, as comparable reaction protocols for α-C-H cyanation frequently occur via free radical mechanisms, and are thus fundamentally limited in their functional group tolerance. In contrast, the presented catalyst system tolerates functional groups that typically react with free radicals, suggesting an alternative reaction pathway. All components of the described system are readily available, allowing implementation of the presented methodology without the need for lengthy catalyst synthesis.Recent mechanistic work in the Fe catalyzed α-C-H oxidation of tertiary amines has uncovered a radical rebound ASSOCIATED CONTENT Supporting Information. Reaction optimization details, synthetic procedures, characterization for new and known compounds.

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Section: Resultsmentioning

confidence: 92%

“…This is notable, since these and similar heterocyclic substrates can form N-oxides in the presence of peroxide oxidants. 32,33 Overall, the intermolecular reaction screening predicts that the protocol should be applicable for the α-C-H cyanation of complex amine substrates.…”

Section: Scheme 3 Substrate Scope Of Aniline Type Tertiarymentioning

confidence: 99%

Iron-Catalyzed α-C–H Cyanation of Simple and Complex Tertiary Amines

2021

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“…and recently examined by our group to classify the reactivity of various N ‐oxides [41] . In addition to the easy accessibility of the starting materials, this reaction is also characterized by a reaction time of a few hours and is therefore of great interest for homogeneous gold catalysis [42–43] . The selection of the N ‐oxides was based on our recent work [44] .…”

Section: Methodsmentioning

confidence: 99%

“…[41] In addition to the easy accessibility of the starting materials, this reaction is also characterized by a reaction time of a few hours and is therefore of great interest for homogeneous gold catalysis. [42][43] The selection of the N-oxides was based on our recent work. [44] For the present study, we examined the efficient 8-methylquinoline N-oxide 6 a reagent, the fast-reacting 3,5-dibromopyridine N-oxide 6 b and pyridine N-oxide 6 c as reference compounds.…”

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confidence: 99%

Water Can Accelerate Homogeneous Gold Catalysis

2021

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A selection of gold-catalyzed reactions was examined in a kinetic study on the influence of water on the rate constant. Two intramolecular reactions and one intermolecular reaction, which proceed via proton transfer and/or protodeauration steps, were investigated. The kinetic data was collected by GC or 1 H NMR spectroscopy. The obtained rate constants provided information about the influence of water in these test reactions. On the basis of the data collected, beyond the commonly assumed tolerance against water, a reaction-promoting influence of water on gold catalysis was identified and kinetically quantified. The results underline that the often-mentioned water-tolerance of gold catalysis not only simplifies these reactions operationally, but in addition even provides better results than a troublesome exclusion of water.

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“…In recent years various processes have been reported by using hydrogen peroxide as a key oxidant with transition metal catalyst such as trifluoroacetic anhydride, methyl rhenium trioxide, but due to its low reactivity towards N‐oxide synthesis, long reaction time and low yield of product has been major concern. Great efforts have been made to develop metal catalyst free approaches to synthesize various N‐oxides by using 2,2,2‐trifluroacetophenone as an Organocatalyst and 1,2‐diphenyl‐1,1‐2,2‐tetrahydroperoxyethane as an oxidant. Although, most of the procedures, meets the criteria of green chemistry, these methods suffer from certain drawbacks, like use of transition metal catalyst, use of heteropolyacids as an activators for peroxide, longer reaction time, non‐recyclable metal oxides, high temperature and utilization of corrosive acids.…”

Section: Introductionmentioning

confidence: 99%

Nonanebis (peroxoic acid)‐Mediated Transition‐Metal‐Free Approach for N‐Oxide Synthesis

2018

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An efficient, metal catalyst free approach for the synthesis of Noxide is described. Nonanebis (peroxoic acid) is used as a source of oxygen, it is non shock sensitive, stable and easy to handle at room temperature. This protocol is applicable for various aromatic as well as aliphatic tertiary amines in good to excellent yields. Less reaction time, optimum temperature, easy workup procedure and metal catalyst free approach is the beauty of the present protocol.

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Catalyst-free and selective oxidation of pyridine derivatives and tertiary amines to corresponding N-oxides with 1,2-diphenyl-1,1,2,2-tetrahydroperoxyethane

Cited by 7 publications

References 47 publications

Iron-Catalyzed α-C–H Cyanation of Simple and Complex Tertiary Amines

Iron-Catalyzed α-C–H Cyanation of Simple and Complex Tertiary Amines

Water Can Accelerate Homogeneous Gold Catalysis

Nonanebis (peroxoic acid)‐Mediated Transition‐Metal‐Free Approach for N‐Oxide Synthesis

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