Single C(sp3)–F Bond Activation in a CF3 Group: Ipso-Defluorooxylation of (Trifluoromethyl)alkenes with Oximes

Zeng, Hao; Zhu, Chuanle; Jiang, Huanfeng

doi:10.1021/acs.orglett.9b00074

Cited by 58 publications

(31 citation statements)

References 70 publications

(25 reference statements)

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“…In 2019, Zhu and Jiang developed an unprecedented base‐mediated regioselective ipso ‐defluorooxylation of trifluoromethylalkenes 245 with oximes 244 , giving a number of O ‐(1,1‐difluoroallyl)oxime ethers 246 in moderate to high yield under transition‐metal‐free conditions (Scheme 64). [91] Preliminary mechanistic investigations indicated that an anionic S N 2‐type substitution process might be involved in this transformation. Additionally, further synthetic applications, for example, hydrogenation, oxidation, and cycloaddition, were also explored.…”

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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“…While effective, these stepwise protocols are unideal from the viewpoint of practicality and step‐economy, thus leaving ample room for the development of more efficient strategy for the α‐selective C−F bond functionalization of alkenyl‐CF 3 . It should be pointed out that an interesting S N 2 type selective defluorinative oxylation of alkenyl‐CF 3 was disclosed by Zhu and Jiang's group, although the competent nucleophile was limited to oxime [17] . Herein, we report a strategically novel protocol for α‐selective C−F bond allylation of trifluoromethylalkenes using allylsilane as both allyl donor and fluoride scavenger under thermal reaction conditions (Scheme 1 c).…”

Section: Methodsmentioning

confidence: 98%

“…It should be pointed out that an interesting S N 2 type selective defluorinative oxylation of alkenyl-CF 3 was disclosed by Zhu and Jiangs group, although the competent nucleophile was limited to oxime. [17] Herein, we report a strategically novel protocol for a-selective C À F bond allylation of trifluoromethylalkenes using allylsilane as both allyl donor and fluoride scavenger under thermal reaction conditions (Scheme 1 c). Several notable features of the present reaction need to be pointed out: 1) a cascade of S N 2' defluorinative allylation and Cope rearrangement enables challenging C À F bond functionalization; 2) a self-sustained silane activation is achieved with the extruded fluoride; 3) fluorine substituents prompt a selective 3,3rearrangement and such effect is attenuated with the reduction of fluorine substitution; 4) the selectivity for mono-CÀF Scheme 1.…”

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confidence: 99%

Selective C–F Bond Allylation of Trifluoromethylalkenes

et al. 2021

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Selective CÀF bond functionalization of CF 3 group represents an appealing strategy for the incorporation of pharmaceutically privileged difluoromethylene moiety. Despite the recent significant advancement attained in the functionalization of Ar-CF 3 molecules, prescriptions amenable for alkenyl-CF 3 congeners remain sufficiently inadequate. Herein, we report a strategically novel protocol for the CÀF bond elaboration of trifluoromethylalkene derivatives. By using readily available allyl metallics as nucleophilic coupling partner, the present reaction enables an expedient construction of structurally diversified CF 2 -bridged 1,5-dienes. Furthermore, the exquisite selectivity observed in this transformation is revealed to be based on the underlying mechanism that consists of a cascade of nucleophilic S N 2' defluorinative allylation and electronically promoted Cope rearrangement.

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“…The protocol is remarkably general, and only alkyl fluorides reacted chemoselectively in the presence of other halides. Zhu and Jiang's group [204] developed a defluorinative ipso-functionalization reaction of (trifluoromethyl)alkenes with oximes through an anionic S N 2-type substitution pathway (Scheme 81). Under the base conditions, various O-(1,1difluoroallyl)oxime ethers (456−461) were synthesized.…”

Section: ) Under Mild Conditionsmentioning

confidence: 99%

C-F bond activation under transition-metal-free conditions

Song

et al. 2021

Sci. China Chem.

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The unique properties of fluorine-containing organic compounds make fluorine substitution attractive for the development of pharmaceuticals and various specialty materials, which have inspired the evolution of diverse C-F bond activation techniques. Although many advances have been made in functionalizations of activated C-F bonds utilizing transition metal complexes, there are fewer approaches available for nonactivated C-F bonds due to the difficulty in oxidative addition of transition metals to the inert C-F bonds. In this regard, using Lewis acid to abstract the fluoride and light/radical initiator to generate the radical intermediate have emerged as powerful tools for activating those inert C-F bonds. Meanwhile, these transition-metal-free processes are greener, economical, and for the pharmaceutical industry, without heavy metal residues. This review provides an overview of recent C-F bond activations and functionalizations under transition-metal-free conditions. The key mechanisms involved are demonstrated and discussed in detail. Finally, a brief discussion on the existing limitations of this field and our perspective are presented.

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Single C(sp³)–F Bond Activation in a CF₃ Group: Ipso-Defluorooxylation of (Trifluoromethyl)alkenes with Oximes

Cited by 58 publications

References 70 publications

Recent Advances in the Synthesis of Difluorinated Architectures from Trifluoromethyl Groups

Recent Advances in the Synthesis of Difluorinated Architectures from Trifluoromethyl Groups

Selective C–F Bond Allylation of Trifluoromethylalkenes

C-F bond activation under transition-metal-free conditions

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