Copper catalyzed photoredox synthesis of α-keto esters, quinoxaline, and naphthoquinone: controlled oxidation of terminal alkynes to glyoxals

Das, Deb K.; Pampana, V. Kishore Kumar; Hwang, Kuo Chu

doi:10.1039/c8sc03447h

Cited by 61 publications

(19 citation statements)

References 59 publications

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“…Sequential Paterno-Buchitype [2+2] cycloaddition of Cu(II)-phenylacetylide and benzoquinone, oxetane ring-opening, fragmentation, formation of a peracid species, CO 2 extrusion, and keto-enol tautomerism furnish the aryl ketone product (Fig. 4B, ii) and aliphatic alcohols in the presence of oxygen, stoichiometric 2-picolinic acid, and catalytic copper(I) iodide furnished a-keto esters in high yields (44). Very recently, a CuCl-catalyzed three-component reaction between N-alkylanilines, terminal alkynes, and primary alcohols in the presence of stoichiometric benzoquinone as an oxidant to furnish propargylamines is reported by the same group (Fig.…”

Section: C(sp 3 /Sp 2 )-Heteroatom Cross-couplingmentioning

confidence: 99%

Copper’s rapid ascent in visible-light photoredox catalysis

Hossain

Bhattacharyya

Reiser

2019

Science

540

302

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Visible-light photoredox catalysis offers a distinct activation mode complementary to thermal transition metal catalyzed reactions. The vast majority of photoredox processes capitalizes on precious metal ruthenium(II) or iridium(III) complexes that serve as single-electron reductants or oxidants in their photoexcited states. As a low-cost alternative, organic dyes are also frequently used but in general suffer from lower photostability. Copper-based photocatalysts are rapidly emerging, offering not only economic and ecological advantages but also otherwise inaccessible inner-sphere mechanisms, which have been successfully applied to challenging transformations. Moreover, the combination of conventional photocatalysts with copper(I) or copper(II) salts has emerged as an efficient dual catalytic system for cross-coupling reactions.

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Section: C(sp 3 /Sp 2 )-Heteroatom Cross-couplingmentioning

confidence: 99%

Copper’s rapid ascent in visible-light photoredox catalysis

Hossain

Bhattacharyya

Reiser

2019

Science

540

302

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“…The cif file of 1 obtained by us is available upon request). The structure of 1 was firstly reported by Takenaka et al., [13r] followed by a number of reports of the same structure with variable quality [13a–q,s–x] . The structure of 2 was reported four times [14] .…”

Section: Resultsmentioning

confidence: 99%

EPR, Magnetic, and Computational Characterization of Linear and Zigzag Ladder‐type Chains of Exchange Coupled Cu(II) Complexes with Picolinic and Dipicolinic Acid Ligands

et al. 2021

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We report magnetic, EPR, and computational studies on two representative examples of structurally well‐characterized one dimension (1D) molecular systems: the copper complexes catena‐[bis(μ‐pyridine‐2‐carboxylato)‐copper dihydrate] and catena‐[(μ2‐pyridine‐2,6‐dicarboxylato)‐diaqua‐copper(II)], hereafter 1 and 2, respectively. Experimental and theoretical results confirmed that the structural chains in both compounds behave as magnetic chains in which the copper ions are weakly coupled by isotropic exchange. Magnetic susceptibility measurements of 1 suggested that the copper ions are antiferromagnetically coupled whereas EPR measurements suggested ferromagnetic coupling at temperature above 100 K which becomes antiferromagnetic at low temperatures. Computational calculations would indicate that the ferromagnetic‐antiferromagnetic change may be due to dCu−Oap shortening on lowering temperature temperature (a fact that was observed experimentally by XRD at low temperatures), which redistributes the small Cu(II) unpaired spin density delocalized on the apical ligand to copper. The 1D magnetic behavior of the zigzag ladder chain of 2 is less detectable than that of the single chain of 1. Magnetic susceptibility measurements in conjunction with computational calculations showed that the pathways that give rise to the 1D ladder transmit ferromagnetic exchange interactions with different strengths, with the stronger interaction being transmitted along the rungs. The role of the weaker exchange interactions transmitted along the rails on the magnetic dimensionality of 2 is analyzed.

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“…Several keto-anilides could be obtained in good to excellent yields employing a variety of electron-deficient anilines and alkynes bearing both aryl and alkyl groups. The same strategy has been applied to the preparation of keto-esters 163 and diketo-sulfoximines (Scheme 89). 164 Scheme 87 Copper-catalyzed asymmetric difunctionalization of 1,3dienes.…”

Section: Alkynesmentioning

confidence: 99%

Multicomponent reactions and photo/electrochemistry join forces: atom economy meets energy efficiency

et al. 2022

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Copper catalyzed photoredox synthesis of α-keto esters, quinoxaline, and naphthoquinone: controlled oxidation of terminal alkynes to glyoxals

Abstract: Controlled oxidation of the terminal CC triple bond using O2 (1 atm) as an oxidant and reagent.

Cited by 61 publications

References 59 publications

Copper’s rapid ascent in visible-light photoredox catalysis

Copper’s rapid ascent in visible-light photoredox catalysis

EPR, Magnetic, and Computational Characterization of Linear and Zigzag Ladder‐type Chains of Exchange Coupled Cu(II) Complexes with Picolinic and Dipicolinic Acid Ligands

Multicomponent reactions and photo/electrochemistry join forces: atom economy meets energy efficiency

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