scholarly journals Mild and selective silicon-mediated access to enantioenriched 1,2-mercaptoamines and β-amino arylchalcogenides

2019 ◽  
Vol 43 (16) ◽  
pp. 6388-6393 ◽  
Author(s):  
Damiano Tanini ◽  
Cosimo Borgogni ◽  
Antonella Capperucci
Keyword(s):  
Ring Opening ◽  
Free Ring ◽  
Metal Free ◽  
Ring Opening Reactions

Metal-free ring opening reactions of activated and unactivated aziridines with different silyl chalcogenides are described.

Direct Synthesis of Nitrones via Transition-Metal-Free Ring-Opening of N-Tosylaziridines with the Nitrogen Atom of Various (E)-Aldoximes and (E)-Ketoximes

Synthesis ◽  
2019 ◽  
Vol 51 (21) ◽  
pp. 4043-4057
Author(s):  
Xing Li ◽  
Wenjing Yan ◽  
Rui Zhang ◽  
Honghong Chang ◽  
Wenchao Gao ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Transition Metal ◽  
Oxygen Atom ◽  
Ring Opening ◽  
Direct Synthesis ◽  
Reaction Conditions ◽  
Free Ring ◽  
Metal Free ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions

The KOH-, K2CO3-, or Et3N-catalyzed ring-opening reaction of N-tosylaziridines using the nitrogen atom of a series of (E)-aldoximes and (E)-ketoximes as a nucleophilic atom instead of an oxygen atom was developed to construct various nitrones under mild reaction conditions. Diverse (E)-aldoximes and (E)-ketoximes were demonstrated to be compatible with this reaction and the products of O-ring-opening reactions were not detected for most examples.

scholarly journals Metal-Free Ring-Opening Metathesis Polymerization

2015 ◽  
Vol 137 (4) ◽  
pp. 1400-1403 ◽  
Author(s):  
Kelli A. Ogawa ◽  
Adam E. Goetz ◽  
Andrew J. Boydston
Keyword(s):  
Ring Opening ◽  
Ring Opening Metathesis Polymerization ◽  
Free Ring ◽  
Metathesis Polymerization ◽  
Metal Free

Phosphazene-Promoted Metal-Free Ring-Opening Polymerization of 1,2-Epoxybutane Initiated by Secondary Amides

2015 ◽  
Vol 48 (21) ◽  
pp. 7755-7764 ◽  
Author(s):  
Laetitia Dentzer ◽  
Caroline Bray ◽  
Sylvie Noinville ◽  
Nicolas Illy ◽  
Philippe Guégan
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Free Ring ◽  
Metal Free ◽  
Secondary Amides

scholarly journals SnCl4-catalyzed Solvent-free Acetolysis of 2,7-Anhydrosialic Acid Derivatives

2019 ◽  
Author(s):  
Kesatebrhan Haile Asressu ◽  
Cheng-Chung Wang
Keyword(s):  
Sialic Acid ◽  
Lewis Acids ◽  
Ring Opening ◽  
Building Blocks ◽  
Solvent Free ◽  
Biologically Active ◽  
Protecting Group ◽  
Free Ring ◽  
Ring Opening Reactions ◽  
Acid Catalyzed

Sialic acid-containing glycans are found in different sialic acid forms and a variety of glycosidic linkages in biologically active glycoconjugates. Hence, the preparation of suitably protected sialyl building blocks requires high attention in order to access glycans in pure form. In this line, various C-5 substituted 2,7-anhydrosialic acid derivatives bearing both electron donating and withdrawing protecting groups were synthesized and subjected to different Lewis acid-catalyzed solvent free ring opening reactions at room temperature in the presence of acetic anhydride. Among the various Lewis acids tested, the desired acetolysized products were obtained in moderate yields under a tin(IV) chloride catalysis system. Our methodology can be extended to regioselective protecting group installation and manipulation towards a number of thiosialoside and halide donors.

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