Organo-photoredox catalyzed defluoroacetalation of α-trifluoromethyl alkenes for synthesis of masked γ,γ-difluoroallylic aldehydes

Xiang, Pan; He, Linying; Li, Hao; Qi, Zhongyu; Zhang, Min; Fu, Qiang; Wei, Jun; Yi, Dong; Wei, Siping

doi:10.1016/j.tetlet.2020.152369

Cited by 18 publications

(7 citation statements)

References 63 publications

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“…Subsequently, Yi and Wei disclosed an organophotoredox catalyzed decarboxylative defluoroacetalation of α ‐trifluoromethylalkenes 207 with glyoxylic acid acetal 208 (Scheme 52). [76] The resulting acetal fragments 209 , smoothly converted into corresponding aldehydes or ketones by direct hydrolysis without an isolating procedure, provided an efficient and direct route to various masked γ , γ ‐difluoroallylic aldehydes and ketones. In general terms, both of these methods show good functional group compatibility and broad substrate scope, enabling their potential application to the late‐stage functionalization of naturally complex and biologically active compounds.…”

Section: Defluorinative Functionalization Of Trifluoromethylalkenesmentioning

confidence: 99%

Recent Advances in the Synthesis of Difluorinated Architectures from Trifluoromethyl Groups

2021

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Fluorine-containing moieties are widely used in the pharmaceutical, agrochemical, and material fields. Thus, these structures are of immense interest in the fields of organic synthesis and medicinal chemistry. Among various fluorinated groups, the difluoromethyl unit has drawn increasing attention due to its unique pharmaceutical properties. In recent years, several methods for the synthesis of difluoromethylated compounds have been rapidly developed. However, most of these methods treat aromatic compounds with excess difluoromethylating reagents, which often contain organometallic compounds, so these transformations are generally less environmentally friendly and atom-economical. In this review, we summarize the recent development of new methods for the synthesis of difluoromethyl motifs or difluoroalkenes from trifluoromethylated aromatic compounds or trifluoromethyl alkenes via single C(sp 3 )À F bond cleavage.1.

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Section: Defluorinative Functionalization Of Trifluoromethylalkenesmentioning

confidence: 99%

Recent Advances in the Synthesis of Difluorinated Architectures from Trifluoromethyl Groups

2021

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“…Taking advantage of these benefits, the reaction was further applied to enrich the DNA-encoded library via the photocatalytic defluorinative coupling of DNA-tagged α-CF3 styrenes and alkyl radical precursors in the open air and aqueous media (Scheme 23b) [65]. The robustness of this visible-light-mediated radical-polar crossover additionelimination protocol for the C-F bond cleavage of α-trifluoromethyl alkenes was further demonstrated by the use of alkylboronic acids (Scheme 24a) [66], CF3SO2Na (Scheme 24b) [67], and glyoxylic acid acetals (Scheme 24c) [68] as the radical precursors. The common feature of the radical sources is their low redox potential to be SET oxidized by excited photocatalyst, producing a one-electron-reduced form of photocatalyst (PC − ) to switch the subsequent α-CF3 carbon radicals to carbon ions.…”

Section: Trifluoromethyl Alkenesmentioning

confidence: 99%

Recent Advances in C-F Bond Cleavage Enabled by Visible Light Photoredox Catalysis

Zhou

2021

Molecules

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The creation of new bonds via C-F bond cleavage of readily available per- or oligofluorinated compounds has received growing interest. Using such a strategy, a myriad of valuable partially fluorinated products can be prepared, which otherwise are difficult to make by the conventional C-F bond formation methods. Visible light photoredox catalysis has been proven as an important and powerful tool for defluorinative reactions due to its mild, easy to handle, and environmentally benign characteristics. Compared to the classical C-F activation that proceeds via two-electron processes, radicals are the key intermediates using visible light photoredox catalysis, providing new modes for the cleavage of C-F bonds. In this review, a summary of the visible light-promoted C-F bond cleavage since 2018 was presented. The contents were classified by the fluorosubstrates, including polyfluorinated arenes, gem-difluoroalkenes, trifluoromethyl arenes, and trifluoromethyl alkenes. An emphasis is placed on the discussion of the mechanisms and limitations of these reactions. Finally, my personal perspective on the future development of this rapidly emerging field was provided.

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“…Zhang and co-workers reported a Pd-catalyzed selective defluoroarylation of ArCF 3 36 with PhB(OH) 2 (37). The key step in this reaction is the oxidative addition of a C-F bond to a Pd center via SET from Pd(0)* 39 to trifluoromethylarene 36 excited by visible light (Scheme 9).…”

Section: Scheme 7 Selective Single C(sp 3 )-F Bond Hydrodefluorinatio...mentioning

confidence: 99%

“…36 Glyoxylic acid acetals 128 are formyl radical equivalents that allow access to a variety of masked ,-difluoroallylic aldehydes 129. 37 1,4-Dihydropyridines 130 and alkylboronic acids 132 are known as simple alkyl radical precursors in many types of photocatalytic reactions. These reagents are also available for the C-F bond transformation of -trifluoromethyl alkenes 77.…”

Section: Scheme 19 Organometallic Reagents For the Generation Of Carb...mentioning

confidence: 99%

C(sp3)–F Bond Transformation of Perfluoroalkyl Compounds Mediated by Visible-Light Photocatalysis: Spin-Center Shifts and Radical/Polar Crossover Processes via Anionic Intermediates

2022

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Precisely controllable C–F bond activation is a significant challenge in organic synthesis due to its large bond energy. A single C(sp3)–F bond transformation of perfluoroalkyl groups is particularly desirable to supply functionalized perfluoroalkyl compounds offering properties that could be significantly useful in pharmaceutical and materials chemistry. Recently, the single defluoronative transformation of perfluoroalkyl compounds was developed via visible-light photocatalysis. Herein, we summarize this field via two main topics. Topic 1 involves the transformation of C(sp3)–F bonds in either perfluoroalkylarenes or perfluoroalkane carbonyl compounds via a defluorinative spin-center shift in the radical anion intermediates. Topic 2 addresses the defluorinative transformation of α-trifluoromethyl alkenes to gem-difluoroalkenes via a radical/polar crossover process.

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Organo-photoredox catalyzed defluoroacetalation of α-trifluoromethyl alkenes for synthesis of masked γ,γ-difluoroallylic aldehydes

Cited by 18 publications

References 63 publications

Recent Advances in the Synthesis of Difluorinated Architectures from Trifluoromethyl Groups

Recent Advances in the Synthesis of Difluorinated Architectures from Trifluoromethyl Groups

Recent Advances in C-F Bond Cleavage Enabled by Visible Light Photoredox Catalysis

C(sp3)–F Bond Transformation of Perfluoroalkyl Compounds Mediated by Visible-Light Photocatalysis: Spin-Center Shifts and Radical/Polar Crossover Processes via Anionic Intermediates

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