Use of a Traceless Activating and Directing Group for the Construction of Trifluoromethylpyrazoles: One‐Pot Transformation of Nitroolefins and Trifluorodiazoethane

Chen, Zhe; Zheng, Yan; Ma, Jun‐An

doi:10.1002/ange.201700955

Cited by 28 publications

(2 citation statements)

References 55 publications

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“…Furthermore, in 2017, an efficient route for accessing 4-substituted 3-trifluoromethylpyrazoles 7 via a traceless activating group strategy has been reported by the same group (Scheme 3). 11 In this strategy, the nitro group activates olefin 6 for the facile 1,3-dipolar cycloaddition of trifluorodiazoethane 2 in a regioselective manner to deliver pyrazoline as an intermediate. Subsequently, it underwent a spontaneous elimination of the nitro group to furnish the corresponding trifluoromethylated pyrazoles 7 .…”

Section: [3 + 2] Cycloaddition Reactions Employing Diazo Compoundsmentioning

confidence: 99%

Recent advances in pyrazole synthesis employing diazo compounds and synthetic analogues

et al. 2022

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Section: [3 + 2] Cycloaddition Reactions Employing Diazo Compoundsmentioning

confidence: 99%

Recent advances in pyrazole synthesis employing diazo compounds and synthetic analogues

et al. 2022

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“…[4] In sharp contrast, the synthetic applications of volatile lowmolecular-weight functionalized diazomethanes are largely underdeveloped. [5] Diazoacetaldehyde (CHOCHN 2 ) [6] and difluorodiazoethane (CF 2 HCHN 2 ) [7] are two valuable lowmolecular-weight diazo compounds that have shown to act as formylating (CHO) and difluoromethylating (CF 2 H) reagents,r espectively.N evertheless,i ns tark contrast to the remarkable achievement in the utility of trifluorodiazoethane (CF 3 CHN 2 )i no rganic synthesis, [8] theb road applicability of CF 2 HCHN 2 and CHOCHN 2 remains in infancy, suffering from difficulties associated with practical generation, storage, and reaction operation.…”

Section: Introductionmentioning

confidence: 99%

Difluoroacetaldehyde N‐Triftosylhydrazone (DFHZ‐Tfs) as a Bench‐Stable Crystalline Diazo Surrogate for Diazoacetaldehyde and Difluorodiazoethane

et al. 2020

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Despite the growing importance of volatile functionalized diazoalkanes in organic synthesis, their safe generation and utilization remain a formidable challenge because of their difficult handling along with storage and security issues. In this study, we developed a bench‐stable difluoroacetaldehyde N‐triftosylhydrazone (DFHZ‐Tfs) as an operationally safe diazo surrogate that can release in situ two low‐molecular‐weight diazoalkanes, diazoacetaldehyde (CHOCHN2) or difluorodiazoethane (CF2HCHN2), in a controlled fashion under specific conditions. DFHZ‐Tfs has been successfully employed in the Fe‐catalyzed cyclopropanation and Doyle–Kirmse reactions, thus highlighting the synthetic utility of DFHZ‐Tfs in the efficient construction of molecule frameworks containing CHO or CF2H groups. Moreover, the reaction mechanism for the generation of CHOCHN2 from CF2HCHN2 was elucidated by density functional theory (DFT) calculations.

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DBU‐Catalyzed [3+3] and [3+2] Annulation Reactions of Azomethine Ylides with α‐Diazocarbonyls as N‐Terminal Electrophiles: Modular, Atom‐Economical Access to 1,2,4‐Triazine and 1,2,4‐Triazole Derivatives

et al. 2018

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The DBU-catalyzed [3 + 3] and [3 + 2] cyclization reactions of azomethine ylides with adiazocarbonyls as N-terminal electrophiles have been developed. These reactions involve a sequential intermolecular nucleophilic addition/intramolecular cyclization/oxidation procedure. By the assembly of readily available starting materials, these transformations offer novel, highly efficient one-pot syntheses of various functionalized 1,2,4-triazine and 1,2,4-triazole derivatives in an atom-economical manner under ambient and metal-free conditions in a high regio-and diastereoselective manner.

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Use of a Traceless Activating and Directing Group for the Construction of Trifluoromethylpyrazoles: One‐Pot Transformation of Nitroolefins and Trifluorodiazoethane

Cited by 28 publications

References 55 publications

Recent advances in pyrazole synthesis employing diazo compounds and synthetic analogues

Recent advances in pyrazole synthesis employing diazo compounds and synthetic analogues

Difluoroacetaldehyde N‐Triftosylhydrazone (DFHZ‐Tfs) as a Bench‐Stable Crystalline Diazo Surrogate for Diazoacetaldehyde and Difluorodiazoethane

DBU‐Catalyzed [3+3] and [3+2] Annulation Reactions of Azomethine Ylides with α‐Diazocarbonyls as N‐Terminal Electrophiles: Modular, Atom‐Economical Access to 1,2,4‐Triazine and 1,2,4‐Triazole Derivatives

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