Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis

Rossi‐Ashton, James A.; Clarke, Aimee K.; Unsworth, William P.; Taylor, Richard J. K.

doi:10.1021/acscatal.0c01923

Cited by 149 publications

(88 citation statements)

References 109 publications

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“…Intermediate II could then undergo a β-scission fragmentation, giving rise to the desired heteroarene phosphonate and the ethyl radical which evolved to ethane by hydrogen-atom transfer. 25 , 26 , 64 − 69…”

Section: Results and Discussionmentioning

confidence: 99%

Highly Efficient Production of Heteroarene Phosphonates by Dichromatic Photoredox Catalysis

Herrera-Luna

Díaz

Jiménez

et al. 2021

ACS Appl. Mater. Interfaces

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A new strategy to achieve efficient aerobic phosphorylation of five-membered heteraroenes with excellent yields using dichromatic photoredox catalysis in a gel-based nanoreactor is described here. The procedure involves visible aerobic irradiation (cold white LEDs) of a mixture containing the heteroarene halide, trisubstituted phospite, N , N -diisopropylethylamine (DIPEA) as sacrificial agent, and catalytic amounts of 9,10-dicyanoanthracene ( DCA ) in the presence of an adequate gelator, which permits a faster process than at the homogeneous phase. The methodology, which operates by a consecutive photoinduced electron transfer (ConPET) mechanism, has been successfully applied to the straightforward and clean synthesis of a number of different heteroarene (furan, thiophene, selenophene, pyrrole, oxazole, or thioxazole) phosphonates, extending to the late-stage phosphonylation of the anticoagulant rivaroxaban. Strategically, employment of cold white light is critical since it provides both selective wavelengths for exciting first DCA (blue region) and subsequently its corresponding radical anion DCA •– (green region). The resultant strongly reducing excited agent DCA •– * is capable of even activate five-membered heteroarene halides (Br, Cl) with high reduction potentials (∼−2.7 V) to effect the C(sp 2 )–P bond formation. Spectroscopic and thermodynamic studies have supported the proposed reaction mechanism. Interestingly, the rate of product formation has been clearly enhanced in gel media because reactants can be presumably localized not only in the solvent pools but also through to the fibers of the viscoelastic gel network. This has been confirmed by field-emission scanning electron microscopy images where a marked densification of the network has been observed, modifying its fibrillary morphology. Finally, rheological measurements have shown the resistance of the gel network to the incorporation of the reactants and the formation of the desired products.

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Section: Results and Discussionmentioning

confidence: 99%

Highly Efficient Production of Heteroarene Phosphonates by Dichromatic Photoredox Catalysis

Herrera-Luna

Díaz

Jiménez

et al. 2021

ACS Appl. Mater. Interfaces

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“…For example, compound 3b reacted with difluoroenolate to form the difluoroalkylated diarylmethane 5 in 83% yield via a Cu(OAc) 2 -catalyzed hydrodifluoroalkylation reaction [ 52 ]. Two other examples were the use of photoredox catalysis to generate acyl anions in situ from aromatic carboxylic acids via a triphenylphosphine-mediated deoxygenation process, followed by reaction with sulfonylated diarylmethane 3b to obtain diarylmethane ketone derivatives 6 and 7 [ 53 ].…”

Section: Resultsmentioning

confidence: 99%

Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

Qu¹,

Huang²,

Li³

et al. 2021

Beilstein J. Org. Chem.

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Chemoselective sulfonylation and isonitrilation reactions for the divergent synthesis of valuable diarylmethyl sulfones and isonitrile diarylmethanes starting from easy-to-synthesize para-quinone methides (p-QMs) and commercially abundant p-toluenesulfonylmethyl isocyanide (TosMIC) by using respectively zinc iodide and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as catalysts were developed. The distinguishing feature of this method is that TosMIC plays a dual role from the same substrates in the reaction: as a sulfonyl source or as an isonitrile source. The synthetic utility of this protocol was also demonstrated in the synthesis of difluoroalkylated diarylmethane 5 and diarylmethane ketone derivatives 6 and 7, which are important core structures in natural products and medicines.

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“…[35][36][37] We employed a direct C-O bond activation strategy via electrochemical generation of the key intermediate of the Mitsunobu reaction. 38,39 Control experiments revealed that the coupling reaction did not proceed in the absence of an electric current, nickel catalyst, ligand, or PPh 3 . Currents ranging from 2 to 4 mA were found to be equally effective (1.1-2.3 mA/cm 2 of graphite).…”

Section: Scheme 6 Proposed Mechanism For the Nickel-catalyzed Crosscoupling Of Aryl Halides With Benzylic Trifluoroboratesmentioning

confidence: 99%

Nickel-Catalyzed Paired Electrochemical Cross-Coupling of Aryl Halides with Nucleophiles

Zhang

Sun

2021

Synthesis

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Electrochemistry has recently gained increased attention as a versatile strategy for achieving challenging transformations at the forefront of synthetic organic chemistry. However, most electrochemical transformations only employ one electrode (anodic oxidation or cathodic reduction) to afford the desired products, while the chemistry that occurs at the counter electrode yields stoichiometric waste. In contrast, paired electrochemical reactions can synchronously utilize the anodic and cathodic reactions to deliver the desired product, thus improving the atom economy and energy efﬁciency of the electrolytic process. This review gives an overview of recent advances in nickel-catalyzed paired electrochemical cross-coupling reactions of aryl/alkenyl halides with different nucleophiles.

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Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis

Cited by 149 publications

References 109 publications

Highly Efficient Production of Heteroarene Phosphonates by Dichromatic Photoredox Catalysis

Highly Efficient Production of Heteroarene Phosphonates by Dichromatic Photoredox Catalysis

Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

Nickel-Catalyzed Paired Electrochemical Cross-Coupling of Aryl Halides with Nucleophiles

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