A Sc(OTf)3-catalyzed highly diastereoselective one-pot sequential [3 + 3] dipolar cycloaddition reaction of aldehyde or ketone, N-alkyl hydroxylamine, and spirocyclopropyl oxindole is developed, allowing facile construction of spirocyclic oxindole-tetrahydro-1,2-oxazines with sufficient structural diversity. The corresponding catalytic enantioselective one-pot protocol of aldehydes is also reported
BPh<sub>3</sub>-Catalyzed [2+3] Cycloaddition of Ph<sub>3</sub>PCCO with Aldonitrones: Access to 5-Isoxazolidinones with Exocyclic Phosphonium Ylide Moieties
作者:Amandeep Brar、Daniel K. Unruh、Natalie Ling、Clemens Krempner
DOI:10.1021/acs.orglett.9b02192
日期:2019.8.16
exocyclic phosphonium ylide functionalities via [2+3] cycloaddition of Ph3PCCO and aldonitrones has been developed and applied in the synthesis of 4-alkylidene-5-isoxazolidinones viaWittig olefination. The reaction proceeds by BPh3 catalysis under mild conditions and with a broad substrate scope. A reaction pathway involving the activation of the aldonitrone via interactions with the Lewis acid BPh3 is
A simple, fast, efficient and eco-friendly procedure was developed for the synthesis of alkyl and aryl-N-methylnitrones. The corresponding nitrones of aromatic aldehydes, aliphatic aldehydes and alicyclic carbonyl compounds were prepared from N-methylhydroxylamine hydrochloride and Na2CO3-Na2SO4 by simply grinding at room temperature without using solvent.
Synthesis of isomeric 2,3,5-trisubstituted perhydropyrrolo[3,4-d]-isoxazole-4,6-diones via 1,3-dipolar cycloaddition reactions
作者:Hamdi Özkan、Yilmaz Yildirir
DOI:10.1002/jhet.395
日期:——
A series of isoxazolidine derivates (isomeric 2,3,5‐trisubstitutedperhydropyrrolo[3,4‐d]isoxazole‐4,6‐diones) used as anti‐inflammatory, immunosuppressive, antibacterial agent, and inhibitor for some enzymes were synthesized. These compounds were prepared by 1,3‐dipolar cycloaddition of N‐methyl maleimide and N‐phenyl maleimide with nitrones. Diastereomeric products obtained in this reaction were separated
合成了一系列异恶唑烷衍生物(2,3,5-三取代的全氢吡咯并[3,4-d]异恶唑-4,6-二酮异构体),用作抗炎药,免疫抑制剂,抗菌剂和某些酶的抑制剂。这些化合物是通过将N-甲基马来酰亚胺和N-苯基马来酰亚胺与硝酮进行1,3-偶极环加成制备的。通过柱色谱分离在该反应中获得的非对映异构体产物并重结晶。通过元素分析和光谱方法(1 H NMR,13 C NMR和FTIR)对所有合成的化合物进行表征。J.杂环化学。(2010)。
4-Dimethylaminopyridine-Mediated [3+3] Cycloaddition of Aza-oxyallyl Cations and Nitrones
作者:Qianfa Jia、Dongli Li、Ming Lang、Kun Zhang、Jian Wang
DOI:10.1002/adsc.201700415
日期:2017.11.10
A new 4‐dimethylaminopyridine (DMAP)‐mediated [3+3] cycloaddition reaction of in situ‐ generated aza‐oxyallylcations with nitrones is reported. This simple and efficient method delivers a series of new motifs in good to excellent yields under mild conditions.