Anionic Triflyldiazomethane: Generation and Its Application for Synthesis of Pyrazole-3-triflones via [3 + 2] Cycloaddition Reaction

Das, Pulakesh; Gondo, Satoshi; Tokunaga, Etsuko; Sumii, Yuji; Shibata, Norio

doi:10.1021/acs.orglett.7b03664

Cited by 29 publications

(8 citation statements)

References 72 publications

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“…In 2018, Shibata and co-workers reported the direct synthesis of pyrazole-3-triflones from compound 584 and nitroalkenes under basic conditions. 240 Pyrazoles of type 585−587 were obtained in 17−84% yield (Scheme 99). Mechanistically, compound 584 reacted with NaOMe to liberate anionic triflyldiazomethane 588.…”

Section: Trifluoromethylthio (Cf 3 S)-substituted Pyrazolesmentioning

confidence: 99%

Fluorinated Pyrazoles: From Synthesis to Applications

2020

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Fluorinated pyrazoles play an important role in medicinal chemistry, drug discovery, agrochemistry, coordination chemistry, and organometallic chemistry. Since the early 1990s, their popularity has grown exponentially. Moreover, more than 50% of all contributions on the topic have been published in the last 5 years. In this review, analysis of novel synthetic approaches to fluorinated pyrazoles that appeared in recent years is performed. A particular emphasis is devoted to a detailed consideration of reaction mechanisms. In addition, the reasons that have led to the ever-increasing popularity of fluorinated pyrazoles in various areas of science are discussed. At the end of the review, several potentially interesting but yet mostly unknown classes of fluorinated pyrazoles are outlined.

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Section: Trifluoromethylthio (Cf 3 S)-substituted Pyrazolesmentioning

confidence: 99%

Fluorinated Pyrazoles: From Synthesis to Applications

2020

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“…Common methods [19] for preparing aryl triflones include oxidation of the corresponding aryl sulfides, trifluoromethylation of aryl sulfonyl fluorides or aryl sulfonates, direct trifluoromethanesulfonylation of aromatic compounds, and thia‐Fries rearrangement of aryl trifluoromethanesulfonates. Yet, the direct introduction of triflyl group onto aromatic rings is still a challenge [19,29–33] . Several of these methods have been tested in our group for the synthesis of ( R )‐6,6′‐Tf 2 ‐BINOL 1 with a variable degree of success.…”

Section: Resultsmentioning

confidence: 99%

(R)‐BINOL‐6,6’‐bistriflone: Shortened Synthesis, Characterization, and Enantioselective Catalytic Applications

et al. 2021

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The title compound, characterized by X‐ray crystallography, was accessed in 4 steps with 92 % ee. and 25 % yield from an O‐protected (R)‐BINOL precursor. This revised synthetic route relied on a chlorosulfonylation reaction, as a shortcut to a previously developed sequence requiring the use of toxic SO2 gas and bromine. The strongly electron‐impoverished (R)‐6,6′‐Tf2‐BINOL proved an effective ligand in metal‐catalyzed enantioselective transformations such as a Zr‐based Mannich‐type reaction. The catalytic species was characterized by X‐ray crystallography as a unique tetrameric metal cluster. The 6,6′‐bistriflone groups also allowed to exalt the H‐bond donor capacity of the BINOL moiety, as illustrated in an organocatalyzed Morita‐Baylis‐Hillman transformation. Theoretical study indicated that the 6,6′‐bistriflone groups induce a drop of the phenol acidity of 5 pKa units in DMSO. Overall, this work simplified the access, completed the characterization, and confirmed the potential of (R)‐6,6′‐Tf2‐BINOL as a promising platform to further elaborate activated chiral metal ligands or organocatalysts.

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“…In this report, a variety of pyrazole triflones were prepared from nitroalkenes having different EWG and EDG. 100 The methodology worked well with differently substituted aryl rings and heterocyclic variants on the nitroolefin counterpart. It is noteworthy to mention that a reactive anionic triflyldiazomethane anionic species was formed in the first step, which was subsequently reacted with nitroalkene to furnish pyrazole triflones (Scheme 42).…”

Section: Synthesis Of Pyrazolesmentioning

confidence: 99%

The Synthesis of Five-Membered N-Heterocycles by Cycloaddition of Nitroalkenes with (In)Organic Azides and Other 1,3-Dipoles

2021

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Cycloaddition reactions have emerged as rapid and powerful method for constructing heterocycles and carbocycles. [3+2] Cycloadditions of nitroalkenes with various 1,3-dipoles have been an interesting research area for many organic chemists. This review outlines the synthesis of N-substituted and NH-1,2,3-triazoles along with other five membered N-heterocycles through cycloaddition reactions of nitroalkene. 1. Introduction 2. Synthesis of 1,2,3-triazoles 2.1.Synthesis of NH-1,2,3-triazoles 2.2.Synthesis of N-substituted 1,2,3-triazoles 3. Synthesis of Pyrrolidines and Pyrroles 4. Synthesis of Pyrazoles 5. Conclusion

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Anionic Triflyldiazomethane: Generation and Its Application for Synthesis of Pyrazole-3-triflones via [3 + 2] Cycloaddition Reaction

Cited by 29 publications

References 72 publications

Fluorinated Pyrazoles: From Synthesis to Applications

Fluorinated Pyrazoles: From Synthesis to Applications

(R)‐BINOL‐6,6’‐bistriflone: Shortened Synthesis, Characterization, and Enantioselective Catalytic Applications

The Synthesis of Five-Membered N-Heterocycles by Cycloaddition of Nitroalkenes with (In)Organic Azides and Other 1,3-Dipoles

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