Asymmetric Synthesis of Bispiro[γ-butyrolactone-pyrrolidin-4,4′-pyrazolone] Scaffolds Containing Two Quaternary Spirocenters via an Organocatalytic 1,3-Dipolar Cycloaddition
Enantiomerically enriched bispiro[γ‐butyrolactone‐pyrrolidin‐4,4′‐pyrazolone] skeletons were synthesized firstly through a simple organocatalytic 1,3‐dipolarcycloaddition reaction between α‐imino γ‐lactones and alkylidene pyrazolones, which afforded a diversity of bispirocyclic scaffolds in high yields and excellent diastereo‐ and enantioselectivities.
Aerobic CuBr<sub>2</sub>-Catalyzed Oxidative Coupling Reaction of Amidines with Exocyclic α,β-Unsaturated Cycloketones for the Synthesis of Spiroimidazolines
A CuBr2-catalyzed cascade reaction of amidines with exocyclic α,β-unsaturated cycloketones was developed, affording a large variety of spiroimidazolines in moderate to excellent yields. The reaction process involved the Michael addition and copper(II)-catalyzed aerobic oxidative coupling, in which O2 from air acted as the oxidant and H2O was the sole byproduct.
Pyridinium Ylide-Mediated Diastereoselective Synthesis of Spirocyclopropanyl-pyrazolones via Cascade Michael/Substitution Reaction
作者:Akanksha Kumari、Dhirajkumar Jitendrabhai Patanvadiya、Anshul Jain、Ranjan Patra、Manikandan Paranjothy、Nirmal K. Rana
DOI:10.1021/acs.joc.3c02879
日期:2024.6.7
We have devised a highly diastereoselective formal [2 + 1] annulation reaction of arylidene/alkylidine-pyrazolones with in situ-generated supported as well as standard pyridinium ylides to construct spirocyclopropanyl-pyrazolones. The cascade approach exhibits a wide range of functional group tolerance, gram-scale capability, and substrate versatility. A diverse range of spirocyclic cyclopropanes was
NIS-Promoted Chemodivergent and Diastereoselective Synthesis of Pyrrolinyl and Cyclopentenyl Spiropyrazolones via Regulated Cyclization of Alkylidene Pyrazolones with Enamino Esters
spiropyrazolone moiety through a Michael addition/iodination/intramolecular nucleophilic substitution sequence. When the reaction was performed in acetonitrile at 100 °C, it furnished pyrrolinyl spiropyrazolones exclusively in an anti configuration through N-attacking cyclization. When the reaction was performed in dimethylsulfoxide at 80 °C in the presence of K2HPO4, it afforded cyclopentenyl spiropyrazolones
已经探索了N-碘代琥珀酰亚胺促进的亚烷基吡唑啉酮与烯胺酯的环化,以通过迈克尔加成/碘化/分子内亲核取代序列构建螺吡唑啉酮部分。当该反应在乙腈中于 100 °C 下进行时,通过 N-攻击环化仅提供反构型的吡咯啉基螺吡唑啉酮。当反应在二甲基亚砜中、80℃、K 2 HPO 4存在下进行时,通过C-攻击环化仅产生顺式构型的环戊烯基螺吡唑啉酮。还提出了一种合理的机制。