scholarly journals A Highly Efficient Glycosidation of Glycosyl Chlorides by Using Cooperative Silver(I) Oxide–Triflic Acid Catalysis

2020 ◽  
Vol 26 (36) ◽  
pp. 8053-8063 ◽  
Author(s):  
Scott A. Geringer ◽  
Yashapal Singh ◽  
Daniel J. Hoard ◽  
Alexei V. Demchenko
Keyword(s):  
Acid Catalysis ◽  
Triflic Acid ◽  
Highly Efficient

Intramolecular Diels–Alder Reactions of Oxazoles, Imidazoles, and Thiazoles

Synthesis ◽  
2020 ◽  
Author(s):  
Peter Wipf ◽  
Thanh T. Nguyen
Keyword(s):  
Natural Products ◽  
Lewis Acid ◽  
Acid Catalysis ◽  
Copper Catalysts ◽  
Diels Alder ◽  
Synthetic Approach ◽  
Highly Efficient ◽  
Intramolecular Cycloadditions ◽  
Western Segment ◽  
Target Molecules

AbstractThe development of the intramolecular Diels–Alder cycloaddition­ of azole heterocycles, i.e. oxazoles (IMDAO), imidazoles (IMDAI), and thiazoles (IMDAT), has had a significant impact on the efficient preparation of heterocyclic intermediates and natural products. In particular, highly efficient and versatile IMDAO reactions have been utilized as a key step in several synthetic schemes to provide alkaloids and terpenoid target molecules. More limited studies have been performed on IMDAI and IMDAT cycloadditions. Some drawbacks, such as the occasionally­ challenging preparation of IMDA precursors, are also highlighted in this review. Perspectives are provided on how IMDAI and IMDAT­ transformations can be further expanded for target-directed syntheses.1 Introduction2 Oxazoles2.1 IMDAO Approaches to Furanosesquiterpenes and Furanosteroids2.1.1 Syntheses of Highly Oxygenated Sesquiterpenes2.1.2 Syntheses of (±)-Gnididione and (±)-Isognididione2.1.3 Synthesis of (±)-Stemoamide2.1.4 Synthesis of (±)-Paniculide A2.1.5 Syntheses of (+)- and (–)-Norsecurinine2.1.6 Synthesis of Evodone2.1.7 Syntheses of (±)-Ligularone and (±)-Petasalbine2.1.8 Syntheses of Imerubrine, Isoimerubrine, and Grandirubrine2.1.9 Syntheses of Furanosteroids2.1.10 Syntheses of Substituted Indolines and Tetrahydroquinolines2.2 IMDAO Approaches to Pyridines: the Kondrat’eva Reaction2.2.1 Syntheses of Suaveoline and Norsuaveoline2.2.2 Synthesis of Eupolauramine2.2.3 Syntheses of (–)-Plectrodorine and (+)-Oxerine2.2.4 Synthesis of Amphimedine2.2.5 Synthetic Approach to the Western Segment of Haplophytine2.2.6 Synthesis of Marinoquinoline A2.2.6.1 IMDAO Approach to Marinoquinoline A2.2.6.2 Scope of Allenyl IMDAO Cycloaddition2.3 Lewis Acid Catalysis in IMDAO Reactions2.3.1 Effects of Europium Catalysts on IMDAO Reactions2.3.2 Effects of Copper Catalysts on IMDAO Reactions3 Imidazoles 4 Thiazoles4.1 Syntheses of Menthane and Eremophilane4.2 Further Comments on the Intramolecular Cycloadditions of Thiocarbonyl Ylides5 Conclusions and Outlook

ChemInform Abstract: Highly Efficient One-Pot Synthesis of 2-Aminobenzoxazoles Using Triflic Acid as a Cyclodesulfurizing Reagent.

ChemInform ◽  
2012 ◽  
Vol 43 (27) ◽  
pp. no-no
Author(s):  
Gopal L. Khatik ◽  
Namita Dube ◽  
Anang Pal ◽  
Vipin A. Nair
Keyword(s):  
Triflic Acid ◽  
One Pot ◽  
Highly Efficient ◽  
One Pot Synthesis

Highly Efficient Direct Allylation of Oxindoles with Simple Allylic Alcohols Enabled by Palladium/Brønsted Acid Catalysis

Synlett ◽  
2014 ◽  
Vol 25 (15) ◽  
pp. 2149-2254 ◽  
Author(s):  
Gaoxi Jiang ◽  
Huameng Yang ◽  
Hui Zhou ◽  
Hongyu Yin ◽  
Chungu Xia
Keyword(s):  
Acid Catalysis ◽  
Allylic Alcohols ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Highly Efficient ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysis

Triflic acid-catalyzed metal-free synthesis of (E)-2-cyanoacrylamides and 3-substituted azetidine-2,4-diones

2018 ◽  
Vol 42 (8) ◽  
pp. 6433-6440 ◽  
Author(s):  
Bapurao D. Rupanwar ◽  
Santosh S. Chavan ◽  
Anil M. Shelke ◽  
Gurunath M. Suryavanshi
Keyword(s):  
Biologically Active ◽  
Efficient Synthesis ◽  
Triflic Acid ◽  
Metal Free ◽  
Highly Efficient ◽  
Acid Catalyzed

A TfOH-catalyzed highly efficient synthesis of biologically active (E)-2-cyanoacrylamides and 3-substituted azetidine-2,4-diones has been reported with 64–94% yields under metal-free conditions.

Surface etching of silicone elastomers by depolymerization

2012 ◽  
Vol 90 (1) ◽  
pp. 153-160 ◽  
Author(s):  
Michael A. Brook ◽  
Shigui Zhao ◽  
Lihua Liu ◽  
Yang Chen
Keyword(s):  
Surface Roughness ◽  
Acid Catalysis ◽  
Silicone Elastomer ◽  
Surface Erosion ◽  
Triflic Acid ◽  
Independent Control ◽  
Silicone Elastomers ◽  
Surface Etching ◽  
Tetrabutylammonium Fluoride ◽  
Judicious Choice

Silicone elastomer surfaces that are rough at the nanometer to micron scales could be useful for biomaterials, but there are few efficient routes for their preparation. Silicones undergo depolymerization under equilibrating conditions. We demonstrate that surface roughness can be induced by depolymerizing silicone elastomers using triflic acid, tetrabutylammonium fluoride or KOH as catalysts. The efficiency of depolymerization, however, is decoupled from the roughness that develops. When the catalysts are dissolved in solvents that do not effectively swell silicones, the etching reaction can be mostly directed to the elastomer surface. Acid catalysis leads to slow, nearly homogenous surface erosion with surface roughnesses only increasing from 15 to about 125 nm root mean squared roughness. By contrast, once KOH partitions into the elastomer, the rate of erosion is more efficient than return of the catalyst to the solvent, leading to deep channels and roughnesses of up to ∼850 nm. The use of fluoride requires good solvents for silicone, and leads to surfaces of intermediate roughness. Thus, judicious choice of catalyst and solvent permits independent control over depolymerization and the induction of surface roughness.

ChemInform Abstract: Highly Efficient [3 + 2] Reaction of 3-Vinylindoles with 3-Indolylmethanols by Broensted-Acid Catalysis.

ChemInform ◽  
2014 ◽  
Vol 45 (41) ◽  
pp. no-no
Author(s):  
Cheng Zhang ◽  
Lan-Xi Zhang ◽  
Yang Qiu ◽  
Biao Xu ◽  
Yu Zong ◽  
...  
Keyword(s):  
Acid Catalysis ◽  
Highly Efficient
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