A Direct C2‐Selective Phenoxylation and Alkoxylation of Quinoline <i>N</i>‐Oxides with Various Phenols and Alcohols in the Presence of <i>H</i>‐Phosphonate

Bi, Wen‐Zhu; Qu, Chen; Chen, Xiaolan; Qu, Lingbo; Liu, Zhi‐Dong; Sun, Kai; Xu, Lijin; Zhao, Yufen

doi:10.1002/ejoc.201701080

“…Taking the inherent electrophilic nature of the 2‐position of quinoline into account, quinoline monomers 2 – 4 , which bear a potentially nucleophilic oxygen functionality at the 8‐position, were selected as precursors (Scheme 1a). In particular, the recently disclosed phosphonate‐mediated deoxygenative etherification of quinoline N ‐oxides [62] drew our attention, as it has the potential to accomplish the three‐fold etherification of readily available and inexpensive 8‐hydroxyquinoline N ‐oxide ( 2 ) to furnish 1 (Scheme 1b and Table S1). However, despite numerous attempts, cyclic products were not observed using this expeditious synthetic route, which we tentatively ascribed to unfavorable electrostatic repulsion between the oxygen and nitrogen atoms located at the interior upon cyclization.…”

Section: Resultsmentioning

confidence: 99%

Oxa‐TriQuinoline: A New Entry to Aza‐Oxa‐Crown Architectures**

Toi

¹

,

Kumagai

²

2023

Angewandte Chemie

0

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A new 15‐membered‐macrocyclic molecular entity, oxa‐TriQuinoline (o‐TQ), was designed and synthesized. In o‐TQ, three oxygen atoms were joined onto three quinoline units at the 2‐ and 8‐positions in a head‐to‐tail fashion by three‐fold SNAr reactions, giving rise to the characteristic N3O3 aza‐oxa‐crown architecture. o‐TQ can serve as a new tridentate nitrogen ligand to capture a CuI cation and adopt a bowl shape, before supramolecular complexation with corannulene and [12]cycloparaphenylene (CPP) occurs through π–π and CH–π interactions. In the presence of the CuI cation, the non‐emissive o‐TQ becomes a highly emissive material in the solid state, whereby the emission wavelengths depend on the ancillary ligand on the CuI cation. The o‐TQ/CuI complex is able to promote carbene catalysis to provide a range of enamines with a gem‐difluorinated terminus.

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“…Finally, the expected product 147 generated from 148 via rearrangement followed by deprotonation (Scheme 54). [76] In 2017, Tomkinson and co-workers [77] have developed three-component reaction of pyridine N-oxides and aryl chlorides in the presence of a cyclic ether at 25-50°C to yield substituted pyridines 151 as a single regioisomer as shown in Scheme 55.…”

Section: Transition Metal Free αà Cà O Bond Formation Of Six Memberedmentioning

confidence: 99%

“…In 2017, Zhao and co‐workers [76] developed an efficient synthesis of 2‐aryloxy (alkoxy)quinoline from quinoline N ‐oxides 18 and alcohols 146 in the presence of H ‐phosphonate. Quinoline N ‐oxides 18 transferred to desired products 147 in the presence of diisopropyl H ‐phosphonate, i Pr 2 EtN and CCl 4 under transition metal free and mild condition (Scheme 54).…”

Section: Introductionmentioning

confidence: 99%

“…Quinoline N ‐oxides 18 transferred to desired products 147 in the presence of diisopropyl H ‐phosphonate, i Pr 2 EtN and CCl 4 under transition metal free and mild condition (Scheme 54). [76] Phenols having electron donating or electron withdrawing groups gave products in good to excellent yields. Also, quinoline N ‐oxides bearing electron donating or electron withdrawing groups provided the desired products in good to excellent yields.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, the expected product 147 generated from 148 via rearrangement followed by deprotonation (Scheme 54). [76] …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Transition Metal Free α−C−H Functionalization of Six Membered Heteroaromatic‐N‐Oxides

Kaur

¹

,

Mandal

²

,

Banerjee

³

et al. 2021

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A comprehensive account of transition metal free αÀ CÀ H functionalization of six membered heteroaromatic-N-oxides has been discussed in this review article. This review includes brief account of explanatory text with schemes, effect of substituents on the reaction and limitation of reaction for transition metal free αÀ CÀ H functionalization of six membered heteroaromatic-N-oxides. Schemes depict the reaction conditions along with a quick look into their mechanism. Each of the reported example has been considered for reacting substrates such as readily available different six membered heteroaromatic-N-oxides, activating reagents, reaction conditions and different types of nucleophiles (N, Halogens, P, S, C and O), reaction conditions and reagents used for transition metal free αÀ CÀ H functionalization of six membered heteroaromatic-Noxides. This review will be supportive to the chemists in understanding the challenges associated with the reported methods as well as the future potentials, both in the choice of substrates and reagents.

show abstract

Oxa‐TriQuinoline: A New Entry to Aza‐Oxa‐Crown Architectures**

Toi

¹

,

Kumagai

²

2023

View full text Add to dashboard Cite

A new 15‐membered‐macrocyclic molecular entity, oxa‐TriQuinoline (o‐TQ), was designed and synthesized. In o‐TQ, three oxygen atoms were joined onto three quinoline units at the 2‐ and 8‐positions in a head‐to‐tail fashion by three‐fold SNAr reactions, giving rise to the characteristic N3O3 aza‐oxa‐crown architecture. o‐TQ can serve as a new tridentate nitrogen ligand to capture a CuI cation and adopt a bowl shape, before supramolecular complexation with corannulene and [12]cycloparaphenylene (CPP) occurs through π–π and CH–π interactions. In the presence of the CuI cation, the non‐emissive o‐TQ becomes a highly emissive material in the solid state, whereby the emission wavelengths depend on the ancillary ligand on the CuI cation. The o‐TQ/CuI complex is able to promote carbene catalysis to provide a range of enamines with a gem‐difluorinated terminus.

show abstract

A Direct C2‐Selective Phenoxylation and Alkoxylation of Quinoline N‐Oxides with Various Phenols and Alcohols in the Presence of H‐Phosphonate

Cited by 17 publications

References 47 publications

Oxa‐TriQuinoline: A New Entry to Aza‐Oxa‐Crown Architectures**

Oxa‐TriQuinoline: A New Entry to Aza‐Oxa‐Crown Architectures**

Transition Metal Free α−C−H Functionalization of Six Membered Heteroaromatic‐N‐Oxides

Oxa‐TriQuinoline: A New Entry to Aza‐Oxa‐Crown Architectures**

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