Diarylborinic Acid-Catalyzed Regioselective Ring Openings of Epoxy Alcohols with Pyrazoles, Imidazoles, Triazoles, and Other Nitrogen Heterocycles

2021 ◽  
Author(s):  
Shrey P. Desai ◽  
Mark S. Taylor
Keyword(s):  
Nitrogen Heterocycles ◽  
Acid Catalyzed ◽  
Epoxy Alcohols

Borinic Acid Catalyzed, Regioselective Chloroacylations and Chlorosulfonylations of 2,3-Epoxy Alcohols

2015 ◽  
Vol 17 (14) ◽  
pp. 3482-3485 ◽  
Author(s):  
Kashif Tanveer ◽  
Kareem Jarrah ◽  
Mark S. Taylor
Keyword(s):  
Acid Catalyzed ◽  
Epoxy Alcohols ◽  
Borinic Acid

Kinetics and Products of the Acid-Catalyzed Ring-Opening of Atmospherically Relevant Butyl Epoxy Alcohols

2010 ◽  
Vol 114 (31) ◽  
pp. 8106-8113 ◽  
Author(s):  
Nathan C. Eddingsaas ◽  
David G. VanderVelde ◽  
Paul O. Wennberg
Keyword(s):  
Ring Opening ◽  
Acid Catalyzed ◽  
Epoxy Alcohols ◽  
Atmospherically Relevant

Borinic Acid-Catalyzed, Regioselective Ring Opening of 3,4-Epoxy Alcohols

2018 ◽  
Vol 20 (17) ◽  
pp. 5375-5379 ◽  
Author(s):  
Grace Wang ◽  
Graham E. Garrett ◽  
Mark S. Taylor
Keyword(s):  
Ring Opening ◽  
Acid Catalyzed ◽  
Epoxy Alcohols ◽  
Borinic Acid

scholarly journals Influence of the Substituents on the Opening of Silylepoxy Alcohols: 5-exo-Cyclization towards Tetrahydrofurans vs. Unexpected Side Reaction Leading to Tetrahydropyrans

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7386
Author(s):  
Carlos Díez-Poza ◽  
Asunción Barbero
Keyword(s):  
Ring Opening ◽  
Side Reaction ◽  
Structural Factors ◽  
Reaction Conditions ◽  
Effect Of Substituents ◽  
Different Types ◽  
Acid Catalyzed ◽  
Epoxy Alcohols

The regioselective ring opening of epoxy alcohols is an effective method for the synthesis of different types of oxacycles. The 5-exo opening being preferred vs. the 6-endo mode, according to Baldwin rules, the use of silyl-substituted oxiranes has been reported as a possible method to favor the 6-endo cyclization. However, there is a need for a detailed study on the different factors (structural factors, catalyst nature or conditions) that influence this process. In this paper, the acid-catalyzed cyclization of epoxysilyl alcohols was studied, focusing on the effect of substituents and reaction conditions on the outcome of the process. Two types of heterocycles (tetrahydrofurans or tetrahydropyrans) were selectively obtained depending on the structure of the initial epoxysilyl alcohol. Interestingly, cyclization of hindered epoxysilyl alcohols mainly proceeds through an unexpected side reaction, which implies a previous isomerization to an aldehyde. A mechanistic proposal for the formation of the different products is presented.

Brønsted acid-catalyzed, enantioselective synthesis of 1,4-dihydroquinoline-3-carboxylates via in situ generated ortho-quinone methide imines

2017 ◽  
Vol 15 (17) ◽  
pp. 3706-3716 ◽  
Author(s):  
Tomáš Hodík ◽  
Christoph Schneider
Keyword(s):  
Phosphoric Acid ◽  
Acid Catalysis ◽  
Nitrogen Heterocycles ◽  
Enantioselective Synthesis ◽  
Quinone Methide ◽  
Keto Esters ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Straightforward Approach

A straightforward approach toward the synthesis of a broad range of 1,4-dihydroquinoline-3-carboxylates is described. Under phosphoric acid catalysis in situ-generated ortho-quinone methide imines reacted with β-keto esters to form the nitrogen heterocycles with good chemical yields and enantioselectivities.

Organocatalyzed [3+3] Annulations for the Construction of Heterocycles

Synthesis ◽  
2020 ◽  
Vol 52 (08) ◽  
pp. 1181-1202
Author(s):  
Yannan Zhu ◽  
You Huang
Keyword(s):  
Nitrogen Heterocycles ◽  
Heterocyclic Carbenes ◽  
Secondary Amines ◽  
Tertiary Amines ◽  
Lewis Bases ◽  
Hydrogen Bonding Interactions ◽  
Chiral Phosphoric Acid ◽  
Oxygen Heterocycles ◽  
Sulfur Heterocycles ◽  
Acid Catalyzed

Six-membered heterocyclic systems are widely distributed in many natural products and pharmaceuticals, and the construction of highly functionalized six-membered heterocyclic compounds is an important topic in modern organic synthesis. Organocatalyzed [3+3] annulations represents an important method for assembling a substantial variety of six-membered cycles that contain one or more heteroatoms. This review describes the development of organocatalyzed [3+3] annulations for the synthesis of six-membered heterocycles, including organocatalysis using secondary amines, tertiary amines, phosphines, chiral phosphoric acids and N-heterocyclic carbenes.1 Introduction2 Secondary Amine Catalyzed [3+3] Annulations2.1 Synthesis of Nitrogen Heterocycles2.2 Synthesis of Oxygen Heterocycles2.3 Synthesis of Sulfur Heterocycles3 Tertiary Amine Catalyzed [3+3] Annulations3.1 Catalysis through Multiple Hydrogen-Bonding Interactions3.2 Catalysis of Tertiary Amines as Lewis Bases4 Phosphine-Catalyzed [3+3] Annulations4.1 Synthesis of Nitrogen Heterocycles4.2 Synthesis of Oxygen Heterocycles4.3 Synthesis of Heterocycles Containing Two or More Heteroatoms5 Chiral Phosphoric Acid Catalyzed [3+3] Annulations5.1 Synthesis of Nitrogen Heterocycles5.2 Synthesis of Heterocycles Containing Two or More Heteroatoms6 N-Heterocyclic Carbene Catalyzed [3+3] Annulations6.1 Synthesis of Nitrogen Heterocycles6.2 Synthesis of Oxygen Heterocycles6.3 Synthesis of Heterocycles Containing Two or More Heteroatoms7 Conclusion and Outlook

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