Chan–Lam Reaction and Lewis Acid Promoted 1,3-Rearrangement of N–O Bonds to Prepare N-(2-Hydroxyaryl)pyridin-2-ones

Bi, Hong-Yan; Wu, Qing-Yan; Zhang, Xiaomei; Xu, Hao; Liang, Cui; Mo, Dong‐Liang; Ma, Xiao‐Pan

doi:10.1021/acs.orglett.2c01827

Cited by 13 publications

(3 citation statements)

References 37 publications

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“…In 2022, Ma et al documented the synthesis of a series of N -(2-hydroxyaryl)pyridin-2-ones via the domino Chan–Lam coupling/1,3 rearrangement protocol. 67 This one-pot methodology was achieved by reacting N -hydroxypyridin-2-ones with aryl boronic acids in the presence of 20 mol% Cu(OAc) 2 , 2 equiv. pyridine in DCE at room temperature for 12 h under air, followed by the introduction of the Lewis acid catalyst BF 3 ·Et 2 O, which promoted the 1,3-rearrangement involving N–O bonds and yielded the required products in high yields at 100 °C (Scheme 64).…”

Section: Classificationmentioning

confidence: 99%

Recent advances in Chan–Lam coupling reaction

Devi,

Saranya,

Anilkumar

2024

Catal. Sci. Technol.

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Section: Classificationmentioning

confidence: 99%

Recent advances in Chan–Lam coupling reaction

Devi,

Saranya,

Anilkumar

2024

Catal. Sci. Technol.

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“…[8,9] In 2022, Ma and the authors reported a Chan-Lam Oarylation of N-hydroxyl-2-pyridinones combined with the Lewis acid promoted 1,3-rearrangement of NÀ O aryl moieties with heating to synthesize N-(2hydroxyaryl)pyridine-2-ols in good yields (Scheme 1-D). [10] Even so, only the [1,3]-rearrangement products were obtained. It is worth noting that the rearrangement proceeded with substituents at the 4-and 5-positions of the N-hydroxyl 2-pyridinones and the formation of the pyridinium salt was the key step in the [1,3]-rearrangement.…”

Section: Introductionmentioning

confidence: 99%

BF₃ ⋅ OEt₂ and Visible Light‐Controlled [3,3]‐ or [1,3]‐Rearrangement of Quinazolinone N−O Aryl Moieties

Nie,

Cheng,

Chen

et al. 2024

Adv Synth Catal

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We described a base‐promoted O‐arylation of N3‐hydroxyl quinazolinones with diaryliodonium salts and sequential BF3·OEt2 and visible light‐controlled [3,3]‐ or [1,3]‐rearrangements of quinazolinone N‐O aryl moieties to prepare a variety of 2‐(quinazolin‐4‐yloxy)phenols and atropisomeric 3‐(2‐hydroxyphenyl)quinazolin‐4‐ones in 44%‐75% yields and 28%‐70% yields, respectively. Mechanistic studies showed that HBF4 generated in situ from BF3·Et2O and water served as the catalyst in this process and aryloxyquinazolinium salts are vital intermediates promoting the [3,3]‐ or [1,3]‐rearrangements. The N‐O aryl moieties of aryloxyquinazolinium salts were found to undergo solely [3,3]‐rearrangement with heating whereas [1,3]‐rearrangement occurred via a radical process under irradiation of visible light. This method highlights the formation of aryloxyquinazolinium salts based on the use of BF3·OEt2 and visible light to prompt [1,3]‐rearrangement generating atropisomeric quinazolinones.

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“…A seminal work has been done mainly to widen the substrate scope and enhance the reaction optimization using the introductory catalyst Cu(OAc) 2 in the presence of a weak base (pyridine, Et 3 N etc.) . However, limited advancement has been achieved in understanding the mechanistic pathways using alternative catalytic systems by modulating the catalytic efficiency or change in reaction conditions such as ligand, solvent, or base .…”

Section: Introductionmentioning

confidence: 99%

7-Azaindole N-Oxide (7-AINO) Mediated Cu-Catalyzed N-Arylation: Mechanistic Investigation into the Role of Fluoride Ions

Mondal,

Mukhopadhyay,

Patra

et al. 2023

ACS Catal.

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A Cu(II) fluoride-catalyzed N-arylation of 7-azaindole N-oxides (7-AINO) has been developed using boronic acid under base-free conditions. During the process, a combination of spectroscopy and crystallography techniques has identified the exact formulation of key reaction intermediates that allowed to propose a complete mechanistic description establishing the role of 7-AINO as a ligand and deducing the crucial role of fluoride ions (F–) in the entire catalytic cycle. A monomeric Cu(II)-7-AINO complex (4) has been detected as a reaction intermediate along with isolation of its dimeric analog (4a) and confirmed by X-ray analysis and mass spectroscopy. The subsequent conversion of Cu(II)-7-AINO complex (4/4a) to catalytically active monomeric fluorinated Cu(II)-complex (I) has been confirmed by 19F NMR, mass, and EPR spectroscopy, reiterating the vital role of fluoride ions in forming the active catalyst. Further, the synthesized Cu(II)-7-AINO complex (4a) in combination with TBAF has been established as an alternative catalytic system for CEL coupling, and its efficiency has been demonstrated for N-arylation of various N-containing nucleophiles. Moreover, a general attempt has been made to promote F– as complementary to the base as well as a CEL catalyst promoter. The role of 7-azaindole-N-oxide (7-AINO) as a ligand was further evaluated, where it acts as an apposite promoter for the Cu-catalyzed N-arylation of azoles in Ullmann-type coupling. The synthetic potential of this methodology is further demonstrated through the synthesis of various pharmaceutically important 7-azaindole annulated derivatives.

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Chan–Lam Reaction and Lewis Acid Promoted 1,3-Rearrangement of N–O Bonds to Prepare N-(2-Hydroxyaryl)pyridin-2-ones

Cited by 13 publications

References 37 publications

Recent advances in Chan–Lam coupling reaction

Recent advances in Chan–Lam coupling reaction

BF₃ ⋅ OEt₂ and Visible Light‐Controlled [3,3]‐ or [1,3]‐Rearrangement of Quinazolinone N−O Aryl Moieties

7-Azaindole N-Oxide (7-AINO) Mediated Cu-Catalyzed N-Arylation: Mechanistic Investigation into the Role of Fluoride Ions

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Chan–Lam Reaction and Lewis Acid Promoted 1,3-Rearrangement of N–O Bonds to Prepare N-(2-Hydroxyaryl)pyridin-2-ones

Cited by 13 publications

References 37 publications

Recent advances in Chan–Lam coupling reaction

Recent advances in Chan–Lam coupling reaction

BF3 ⋅ OEt2 and Visible Light‐Controlled [3,3]‐ or [1,3]‐Rearrangement of Quinazolinone N−O Aryl Moieties

7-Azaindole N-Oxide (7-AINO) Mediated Cu-Catalyzed N-Arylation: Mechanistic Investigation into the Role of Fluoride Ions

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BF₃ ⋅ OEt₂ and Visible Light‐Controlled [3,3]‐ or [1,3]‐Rearrangement of Quinazolinone N−O Aryl Moieties