Ring-Opening Reactions of MCPs with Sulfonamides Promoted by Metal Triflate Lewis Acids

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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Synthesis of nitrile coordinated Lewis acids Al(OC(CF3)2R)3 and their application in catalytic epoxide ring-opening reactions

Applied Catalysis A General ◽

10.1016/j.apcata.2010.06.029 ◽

2010 ◽

Vol 384 (1-2) ◽

pp. 171-176 ◽

Cited By ~ 19

Author(s):

Yang Li ◽

Yi Tan ◽

Eberhardt Herdtweck ◽

Mirza Cokoja ◽

Fritz E. Kühn

Keyword(s):

Lewis Acids ◽

Ring Opening ◽

Epoxide Ring ◽

Epoxide Ring Opening ◽

Ring Opening Reactions

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Ring-opening and ring-expansion reactions of carborane-fused borirane

Chemical Science ◽

10.1039/d1sc04453b ◽

2021 ◽

Vol 12 (39) ◽

pp. 13187-13192

Author(s):

Hanqiang Wang ◽

Jie Zhang ◽

Zuowei Xie

Keyword(s):

Lewis Acids ◽

Ring Opening ◽

Ring Expansion ◽

Ring Opening Reactions ◽

Different Types

Carborane-fused borirane can not only engage in ring-opening reactions with different types of Lewis acids, but also undergo ring-expansion reactions with unsaturated molecules such as PhCHO, CO2 and PhCN to give five-membered boracycles.

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Lewis acids catalyzed ring-opening reactions of methylenecyclopropanes and epoxides in supercritical carbon dioxide or modified supercritical carbon dioxide with perfluorocarbon

Journal of Fluorine Chemistry ◽

10.1016/s0022-1139(03)00083-6 ◽

2003 ◽

Vol 122 (2) ◽

pp. 219-227 ◽

Cited By ~ 27

Author(s):

Min Shi ◽

Yu Chen

Keyword(s):

Carbon Dioxide ◽

Supercritical Carbon Dioxide ◽

Lewis Acids ◽

Ring Opening ◽

Ring Opening Reactions ◽

Supercritical Carbon

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Asymmetric catalysis in aqueous media

Pure and Applied Chemistry ◽

10.1351/pac200779020235 ◽

2007 ◽

Vol 79 (2) ◽

pp. 235-245 ◽

Cited By ~ 57

Author(s):

Shū Kobayashi

Keyword(s):

Asymmetric Catalysis ◽

Lewis Acids ◽

Ring Opening ◽

Acid Catalysis ◽

Aqueous Media ◽

Asymmetric Reactions ◽

Epoxide Ring ◽

Mild Conditions ◽

Ring Opening Reactions ◽

Bipyridine Ligand

Lewis acid catalysis has attracted much attention in organic synthesis because of unique reactivity and selectivity attained under mild conditions. Although various kinds of Lewis acids have been developed and applied in industry, these Lewis acids must be generally used under strictly anhydrous conditions. The presence of even a small amount of water handles the reactions owing to preferential reactions of the Lewis acids with water rather than the substrates. In contrast, rare earth and other metal complexes have been found to be water-compatible. Several catalytic asymmetric reactions in aqueous media, including hydroxymethylation of silicon enolates with an aqueous solution of formaldehyde in the presence of Sc(OTf)3-chiral bipyridine ligand or Bi(OTf)3-chiral bipyridine ligand, Sc- or Bi-catalyzed asymmetric meso-epoxide ring-opening reactions with amines, and asymmetric Mannich-type reactions of silicon enolates with N-acylhydrazones in the presence of a chiral Zn catalyst have been developed. Water plays key roles in these asymmetric reactions.

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SnCl4-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.15.295 ◽

2019 ◽

Vol 15 ◽

pp. 2990-2999

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 a pure form. In line with this, 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 acetolysis products were obtained in moderate yields under tin(IV) chloride catalysis. Our methodology could be extended to regioselective protecting group installations and manipulations towards a number of thiosialoside and halide donors.

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