Synthesis of glycan fragments of glycoproteins using peracetylated N-allyloxycarbonyl-β-D-glucosamine and 1,6-anhydro-β-D-mannopyranose derivatives

1990 ◽  
Vol 68 (6) ◽  
pp. 828-835 ◽  
Author(s):  
Dominique Lafont ◽  
Paul Boullanger ◽  
Joseph Banoub ◽  
Gerard Descotes
Keyword(s):  
Lewis Acid ◽  
Free Amino ◽  
Acid Catalyzed ◽  
High Yields

The disaccharides β-D-GlcNAOC-(1 → 2)-D-Man, β-D-GlcNAOC-(1→ 4)-D-Man, the trisaccharide β-D-GlcNAOC-(1 → 2)-[β-D-GlcNAOC-(1→ 4)]-D-Man, and the tetrasaccharide β-D-GlcNAOC-(1 → 2)-[β-D-GlcNAOC-(1→ 3)]-[β-D-GlcNAOC-(1 → 4)]-D-Man have been synthesized in their peracetylated form, using the Lewis acid catalyzed condensations of 1,3,4,6-tetra-O-acetyl-2-N-allyloxycarbonylamino-2-deoxy-β-D-glucopyranose 1 with properly substituted 1,6-anhydro-β-D-mannopyranose derivatives. The anhydro glycosylation products obtained were then easily transformed into the 4C1 peracetylated derivatives by acetolysis. The N-allyloxycarbonyl groups could be converted into N-acetyl groups in the presence of Pd(0) complexes, followed by reacetylation of the free amino function in high yields. Keywords: N-allyloxycarbonyl, glycosylation, glucosamine, glycan fragments.

Efficient Synthesis of Diarylmethylamines via Lewis Acid Catalyzed Friedel–Crafts Reactions of Donor–Acceptor Aziridines with N,N-Dialkylanilines

Synthesis ◽  
2019 ◽  
Vol 52 (02) ◽  
pp. 281-289
Author(s):  
Yerin Kim ◽  
Yong Il Kwon ◽  
Sung-Gon Kim
Keyword(s):  
Lewis Acid ◽  
Efficient Synthesis ◽  
Broad Scope ◽  
Donor Acceptor ◽  
Acid Catalyzed ◽  
High Yields

A method for efficient and mild synthesis of diarylmethylamine scaffold, via Lewis acid catalyzed Friedel–Crafts reaction of donor­–acceptor aziridines with N,N-dialkylanilines to afford a biologically important diarylmethylamine derivatives in high yields (up to 88%), is presented. This reaction is suitable for the synthesis of various diarylmethylamine derivatives and has a broad scope for electron-rich arenes, including dimethoxybenzene.

Lewis Acid-Catalyzed Rearrangement of Fluoroalkylated Propargylic Alcohols: An Alternative Approach to β-Fluoroalkyl-α,β-enones

Synlett ◽  
2019 ◽  
Vol 30 (03) ◽  
pp. 356-360 ◽  
Author(s):  
Manickavasakam Ramasamy ◽  
Hui-Chang Lin ◽  
Sheng-Chu Kuo ◽  
Min-Tsang Hsieh
Keyword(s):  
Lewis Acid ◽  
Propargylic Alcohols ◽  
Alternative Approach ◽  
Acid Catalyzed ◽  
High Yields ◽  
High Stereoselectivity

A practical Lewis acid-catalyzed Meyer–Schuster rearrangement of fluoroalkylated propargylic alcohols, leading to a series of β-fluoroalkyl-α,β-enones, is developed. The methodology reported herein features moderate to high yields and high stereoselectivity in the synthesis of β-alkyl-β-fluoroalkyl-α,β-enones.

scholarly journals Lewis acid-catalyzed redox-neutral amination of 2-(3-pyrroline-1-yl)benzaldehydes via intramolecular [1,5]-hydride shift/isomerization reaction

2014 ◽  
Vol 10 ◽  
pp. 2892-2896 ◽  
Author(s):  
Chun-Huan Jiang ◽  
Xiantao Lei ◽  
Le Zhen ◽  
Hong-Jin Du ◽  
Xiaoan Wen ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Reducing Power ◽  
Isomerization Reaction ◽  
Hydride Shift ◽  
Acid Catalyzed ◽  
High Yields

Lewis acid-catalyzed redox-neutral amination of 2-(3-pyrroline-1-yl)benzaldehydes via intramolcular [1,5]-hydride shift/isomerization reaction has been realized, using the inherent reducing power of 3-pyrrolines. A series of N-arylpyrrole containing amines are obtained in high yields.

Facile Synthesis of Oxime Amino Ethers via Lewis Acid Catalyzed SN2-Type Ring Opening of Activated Aziridines with Aryl Aldehyde Oximes

Synlett ◽  
2020 ◽  
Vol 31 (07) ◽  
pp. 708-712
Author(s):  
Aditya Bhattacharyya ◽  
Subhomoy Das ◽  
Navya Chauhan ◽  
Pronay K. Biswas ◽  
Manas K. Ghorai
Keyword(s):  
Lewis Acid ◽  
Ring Opening ◽  
Facile Synthesis ◽  
Simple Strategy ◽  
Wide Range ◽  
Aryl Aldehyde ◽  
Acid Catalyzed ◽  
High Yields

A simple strategy to access a wide range of substituted oxime amino ethers in good to high yields via Lewis acid catalyzed SN2-type ring opening of activated aziridines with aryl aldehyde oximes is reported.

Stereoselective synthesis of 3-spiropiperidino indoleninesviaSN2-type ring opening of activated aziridines with 1H-indoles/Pd-catalyzed spirocyclization with propargyl carbonates

2018 ◽  
Vol 54 (62) ◽  
pp. 8583-8586 ◽  
Author(s):  
Sajan Pradhan ◽  
Chandan Kumar Shahi ◽  
Aditya Bhattacharyya ◽  
Manas K. Ghorai
Keyword(s):  
Lewis Acid ◽  
Ring Opening ◽  
Stereoselective Synthesis ◽  
Synthetic Route ◽  
Acid Catalyzed ◽  
High Yields

A novel synthetic route to 3-spiropiperidino indoleninesviaLewis acid catalyzed SN2-type ring opening of activated aziridines with 1H-indoles followed by Pd-catalyzed spirocyclization with propargyl carbonates in high yields (up to 88%) with excellent diastereo- and enantiospecificity (dr >99 : 1; ee up to >99) is reported.

Highly diastereoselective access to polyfunctionalized 1,3-oxazines promoted by Brønsted/Lewis acids

2018 ◽  
Vol 5 (4) ◽  
pp. 566-570 ◽  
Author(s):  
Clovis Peter ◽  
Philippe Geoffroy ◽  
Michel Miesch
Keyword(s):  
Lewis Acid ◽  
Lewis Acids ◽  
Unsaturated Ketones ◽  
Acid Catalyzed ◽  
High Yields

The Brønsted/Lewis acid catalyzed reaction of α-alkyloxyamides tethered to α,β-unsaturated ketones (aldehydes) afforded exclusively polyfunctionalized 1,3-oxazines with high diastereoselectivities and in high yields.

scholarly journals Diastereoselective Addition of Prochiral Nucleophilic Alkenes to a-Chiral N-Sulfonyl Imines

2021 ◽  
Author(s):  
Jared Shaw ◽  
David Gutierrez ◽  
James Fettinger ◽  
Kaori Ando ◽  
Kendall Houk
Keyword(s):  
Lewis Acid ◽  
Computational Analysis ◽  
High Selectivity ◽  
Ether Group ◽  
Carbon Bond ◽  
Stereochemical Control ◽  
Carbon Carbon Bond ◽  
Diastereoselective Addition ◽  
Acid Catalyzed ◽  
High Yields

The Lewis acid catalyzed addition of prochiral E and Z allyl nucleophiles to chiral -alkoxy N-tosyl imines is described. Alkene geometry is selectively transferred to the newly formed carbon-carbon bond, resulting in stereochemical control of C2, C3, and C4 of the resulting 2-alkoxy-3-N-tosyl-4-alkyl-5-hexenes. The C3 and C4 diastereoselectivity (dr) is influenced by the geometry of the alkene, size of N-sulfonyl substituent, and steric bulk of the substituted -alkoxy ether group. This work demonstrates that three of the four possible diastereomers can be synthesized in high diastereoselectivity and high yields using the current methods. A mechanistic computational analysis to elucidate the high selectivity is also presented.

Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) HomoDimers as Lewis Acidic Superelectrophiles

2018 ◽  
Author(s):  
Haley Albright ◽  
Paul S. Riehl ◽  
Christopher C. McAtee ◽  
Jolene P. Reid ◽  
Jacob R. Ludwig ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Acid Activation ◽  
Lewis Acid Catalysts ◽  
Distinct Mode ◽  
Aliphatic Ketones ◽  
Carbon Carbon Bond ◽  
Metathesis Reactions ◽  
Acid Catalyzed

<div>Catalytic carbonyl-olefin metathesis reactions have recently been developed as a powerful tool for carbon-carbon bond</div><div>formation. However, currently available synthetic protocols rely exclusively on aryl ketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in situ formation of a homobimetallic singly-bridged iron(III)-dimer as the active catalytic species. These “superelectrophiles” function as more powerful Lewis acid catalysts that form upon association of individual iron(III)-monomers. While this mode of Lewis acid activation has previously been postulated to exist, it has not yet been applied in a catalytic setting. The insights presented are expected to enable further advancement in Lewis acid catalysis by building upon the activation principle of “superelectrophiles” and broaden the current scope of catalytic carbonyl-olefin metathesis reactions.</div>

scholarly journals Comparison of Corn Stover Pretreatments with Lewis Acid Catalyzed Choline Chloride, Glycerol and Choline Chloride-Glycerol Deep Eutectic Solvent

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1170
Author(s):  
Yuan Zhu ◽  
Benkun Qi ◽  
Xinquan Liang ◽  
Jianquan Luo ◽  
Yinhua Wan
Keyword(s):  
Corn Stover ◽  
Lewis Acid ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Enzymatic Saccharification ◽  
Glycerol Solution ◽  
Cellulose Conversion ◽  
Biomass Processing ◽  
Acid Catalyzed ◽  
Highly Correlated

Herein, corn stover (CS) was pretreated by less corrosive lewis acid FeCl3 acidified solutions of neat and aqueous deep eutectic solvent (DES), aqueous ChCl and glycerol at 120 °C for 4 h with single FeCl3 pretreatment as control. It was unexpected that acidified solutions of both ChCl and glycerol were found to be more efficient at removing lignin and xylan, leading to higher enzymatic digestibility of pretreated CS than acidified DES. Comparatively, acidified ChCl solution exhibited better pretreatment performance than acidified glycerol solution. In addition, 20 wt% water in DES dramatically reduced the capability of DES for delignification and xylan removal and subsequent enzymatic cellulose saccharification of pretreated CS. Correlation analysis showed that enzymatic saccharification of pretreated CS was highly correlated to delignification and cellulose crystallinity, but lowly correlated to xylan removal. Recyclability experiments of different acidified pretreatment solutions showed progressive decrease in the pretreatment performance with increasing recycling runs. After four cycles, the smallest decrease in enzymatic cellulose conversion (22.07%) was observed from acidified neat DES pretreatment, while the largest decrease (43.80%) was from acidified ChCl pretreatment. Those findings would provide useful information for biomass processing with ChCl, glycerol and ChCl-glycerol DES.

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