Copper-catalyzed pyrrole synthesis from 3,6-dihydro-1,2-oxazines

Yasukawa, Naoki; Kuwata, Marina; Imai, Toshiro; Monguchi, Yasunari; Sajiki, Hironao; Sawama, Yoshinari

doi:10.1039/c8gc01373j

Cited by 29 publications

(21 citation statements)

References 44 publications

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“…Natural products, trichodermamide A−C, petrichodermamide A, aspergillazine A, and gliovirin, consist 1,2‐oxazine skeleton, and these natural products possess exciting biological activities [11] . The synthetic methodology discussed in this study might have a good value for the synthesis of natural products or famous rings [12] …”

Section: Methodsmentioning

confidence: 99%

Gold‐catalyzed Cyclization of Non‐conjugated Ynone‐oxime Derivatives: Incorporation of Solvent Molecule

Taşdemir

Mengeş

2020

Asian J Org Chem

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Au ııı-promoted cyclization reaction of ynoneoxime derivatives furnished 4H-1,2-oxazine ring under mild reaction conditions. When an alcohol is present in the reaction media, it was attached to the oxazine ring by the second activation of cyclic intermediate with a gold catalyst. Cholesterol, propargyl alcohol, phenol, and some of the different alcohol derivatives with alkyl chain were bonded to the oxazine ring in good yields. While amine derivatives did not attach to the ring under optimized reaction conditions, the molecule with the thiol group deactivated the gold catalyst under the same reaction conditions and did not give any cyclic products. With the obtained cyclization protocol, 11 unknown oxazine derivatives were synthesized and characterized. The proposed cyclization mechanism was drawn according to the two independent control experiments, DFT optimization, and NBO charges.

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Section: Methodsmentioning

confidence: 99%

Gold‐catalyzed Cyclization of Non‐conjugated Ynone‐oxime Derivatives: Incorporation of Solvent Molecule

Taşdemir

Mengeş

2020

Asian J Org Chem

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“…As a possible pathway, the N−O bond cleavage of 3 can be initiated by the oxidative addition of Cu 0 to form intermediate A (path A), [14] which undergoes a ligand‐exchange with H 2 O to give the corresponding product ( 4 ) and Cu(OH) 2 (Scheme 3). A part of the generated Cu II species can be converted by Cu 0 to Cu I [18] .…”

Section: Resultsmentioning

confidence: 99%

Copper‐Catalyzed Aqueous N−O Bond Cleavage of 2‐Oxa‐3‐Azabicyclo Compounds to Cyclic cis‐1,4‐Amino Alcohols

et al. 2020

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The N−O bond cleavage of 2‐oxa‐3‐azabicyclo substrates, which are readily prepared by the hetero Diels‐Alder reaction between nitroso dienophiles and cyclic 1,3‐dienes, was effectively catalyzed by heterogeneous copper‐on‐carbon (Cu/C) under aqueous conditions to give the corresponding cyclic cis‐1,4‐amino alcohol derivatives. The present method was applied to the direct incorporation of the hydroxy and amino groups derived from a nitroso substrate into cyclic 1,3‐dienes with cis‐selectivity by the combination of the in situ formation of 2‐oxa‐3‐azabicyclo compounds and following Cu/C‐catalyzed N−O bond cleavage. The obtained cis‐4‐aminocyclohexenols, derived from cyclohexadiene as a cyclic 1,3‐diene, could be selectively oxidized by using the ruthenium‐on‐carbon (Ru/C) catalyst under oxygen atmosphere to the corresponding 4‐aminocyclohexenones at 50–65 °C or para‐iminoquinones at 100–110 °C as useful reactive synthetic precursors.

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“…In this regard Sawama, Sajiki and co-workers reported a greener approach towards highly-functionalized pyrrole synthesis (Scheme 4) from 3,6-dihydro-1,2oxazines (12) using heterogeneous copper on carbon (Cu/C) as a catalyst. [15] The oxazine can be easily synthesized from nitroso compounds (10) and 1,3-dienes (11) by Diels-Alder reaction. The scope of the substrate was investigated varying the substitutions in oxazine (Scheme 5).…”

Section: Pyrrole Synthesismentioning

confidence: 99%

Copper in Efficient Synthesis of Aromatic Heterocycles with Single Heteroatom

Pal

Lahiri

2020

Eur J Org Chem

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Aromatic heterocycles are important structural units in various naturally occurring compounds. Its abundance has drawn attention of synthetic chemists for decades. In the current scenario, new methodologies employing cheap transition metal reagents are highly desirable for efficient and practical synthesis of heterocyclic compounds. In this review article, strategies to synthesize aromatic heterocycles by inexpensive copper reagents have been discussed.

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Copper-catalyzed pyrrole synthesis from 3,6-dihydro-1,2-oxazines

Abstract: The highly-functionalized pyrroles could be efficiently synthesized from 3,6-dihydro-1,2-oxazines using only heterogeneous Cu/C under neat heating conditions.

Cited by 29 publications

References 44 publications

Gold‐catalyzed Cyclization of Non‐conjugated Ynone‐oxime Derivatives: Incorporation of Solvent Molecule

Gold‐catalyzed Cyclization of Non‐conjugated Ynone‐oxime Derivatives: Incorporation of Solvent Molecule

Copper‐Catalyzed Aqueous N−O Bond Cleavage of 2‐Oxa‐3‐Azabicyclo Compounds to Cyclic cis‐1,4‐Amino Alcohols

Copper in Efficient Synthesis of Aromatic Heterocycles with Single Heteroatom

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