Room-Temperature Direct Alkenylation of 3-Arylsydnones
作者:Yiwen Yang、Chunxiang Kuang
DOI:10.1002/ejoc.201403211
日期:2014.12
A new efficient method for the directalkenylation of 3-arylsydnones by palladium-catalyzed C–H functionalization was developed. The reaction proceeded smoothly at room temperature and delivered the product in yields up to 83 %.
Exploiting Synergistic Catalysis for an Ambient Temperature Photocycloaddition to Pyrazoles
作者:Christopher P. Lakeland、David W. Watson、Joseph P. A. Harrity
DOI:10.1002/chem.201904210
日期:2020.1.2
Sydnone-based cycloaddition reactions are a versatile platform for pyrazole synthesis, however they operate under harsh conditions (high temperature and long reaction times). Herein we report a strategy that addresses this limitation utilizing the synergistic combination of organocatalysis and visible-light photocatalysis. This new approach proceeds under ambient conditions and with excellent levels
reactivity towards both copper‐catalyzed and strain‐promoted cycloaddition reactions with alkynes. Synthetic access to these new mesoionic compounds was granted by electrophilic fluorination of σ‐sydnone PdII precursors in the presence of Selectfluor. Their reactions with terminal and cyclic alkynes were found to proceed very rapidly and selectively, affording 5‐fluoro‐1,4‐pyrazoles with bimolecular
我们报告了4-氟丁酮的合成和反应性,这是一类独特的中离子偶极子,对炔烃的铜催化和应变促进的环加成反应均显示出出色的反应性。在Selectfluor的存在下,通过σ-sydnonePd II前体的亲电氟化反应,可以合成这些新的中离子化合物。发现它们与末端和环状炔烃的反应非常迅速且选择性地进行,从而提供双分子速率常数高达10 4 m -1 s -1的5-氟-1,4-吡唑,超过了文献中有关环炔烃的文献记载。进行了动力学研究以阐明反应的机理,并成功地用[ 18 F] Selectfluor进行了放射性标记,进一步突出了4-氟丁酮的价值。
Acylation of Sydnones with Acetic Anhydride in the Presence of Montmorillonite K-10
作者:Kenneth Turnbull、Jones C. George
DOI:10.1080/00397919608004593
日期:1996.7
Abstract Various 4-acetyl sydnones 2 can be prepared in good yield by reaction of the corresponding 3-arylsydnones (cf. 1) with acetic anhydride at ∼ 110°C catalyzed by Montmorillonite K-10. The reaction fails where an ortho-keto moiety is present; therein sydnone ring cleavage occurs to form the corresponding indazole 3.