Electrophilic Substitution at Saturated Carbon. XIX. Nitrogen as Leaving Group from an Alkyl Diimide

1963 ◽  
Vol 85 (8) ◽  
pp. 1108-1118 ◽  
Author(s):  
Donald J. Cram ◽  
Jerald S. Bradshaw
Keyword(s):  
Electrophilic Substitution ◽  
Leaving Group

Nitrogen as Leaving Group in Electrophilic Substitution at Saturated Carbon

1962 ◽  
Vol 84 (14) ◽  
pp. 2832-2833 ◽  
Author(s):  
Donald J. Cram ◽  
Jerald S. Bradshaw ◽  
Walter. Lwowski ◽  
Graham R. Knox
Keyword(s):  
Electrophilic Substitution ◽  
Leaving Group

General Cyclopropane Assembly via Enantioselective Redox-Active Carbene Transfer to Aliphatic Olefins

2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Chemical Space ◽  
Synthetic Approach ◽  
Asymmetric Cyclopropanation ◽  
Redox Active ◽  
Wide Range ◽  
Leaving Group ◽  
Stereoelectronic Properties ◽  
Carbene Transfer

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates and reagents, even when targeting similar compounds. This limits the speed and chemical space available for discovery campaigns. Here we introduce a practical and versatile diazocompound, and we demonstrate its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. We found that the redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect enabled the asymmetric cyclopropanation of a wide range of olefins including unactivated aliphatic alkenes, enabling the 3-step total synthesis of (–)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally-differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons<i>.</i>

The Chemistry of Triazine Isomers: Structures, Reactions, Synthesis and Applications

2020 ◽  
Vol 20 ◽  
Author(s):  
Neelottama Kushwaha ◽  
C S Sharma
Keyword(s):  
Basic Property ◽  
Electrophilic Substitution ◽  
Antimicrobial Agents ◽  
Resonance Energy ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Agricultural Fields ◽  
Substitution Reactions ◽  
Anti Cancer ◽  
Benzene Structure

: Triazine is the six-membered heterocyclic ring containing three nitrogen which replaces carbon-hydrogen unit in the benzene ring. Based on nitrogen position present in the ring system, it is categorized in three isomeric forms i.e.1, 2, 3-triazine (vicinal triazine), 1, 2, 4-triazine (asymmetrical triazine or isotriazine) and 1, 3, 5-triazine (symmetrical or s-triazine or cyanidine). Triazines have weakly basic property. Its isomers have much weaker resonance energy than benzene structure, so nucleophilic substitution reactions are more preferred than electrophilic substitution reactions. Triazine isomers and their derivatives are known to play important roles possessing various activities in medicinal and agricultural fields such as anti-cancer, antiviral, fungicidal, insecticidal, bactericidal, herbicidal, antimalarial and antimicrobial agents.

Allylic Amination via Acid Catalyzed Leaving Group Activation

2016 ◽  
Vol 3 (2) ◽  
pp. 145-159
Author(s):  
Marija Skvorcova ◽  
Aigars Jirgensons
Keyword(s):  
Allylic Amination ◽  
Leaving Group ◽  
Acid Catalyzed

Oxidation of polysubstituted pyridinium salts

1982 ◽  
Vol 47 (5) ◽  
pp. 1494-1502 ◽  
Author(s):  
Petr Nesvadba ◽  
Josef Kuthan
Keyword(s):  
Alkaline Medium ◽  
Electrophilic Substitution ◽  
Pyridine Ring ◽  
Potassium Ferricyanide ◽  
Pyridinium Salts ◽  
Complex Reaction

Oxidation of 1-substituted 2,4,6-triphenylpyridinium salts Ia-Ij with potassium ferricyanide in an alkaline medium was accompanied by contraction of the pyridine ring and formation of 1,2,3,5-tetrasubstituted pyrroles II. The derivative IIf underwent facile electrophilic substitution in the position 4. Contrary to compounds Ia-Ij, the 1-substituted-2,6-diphenylpyridinium salts IIIa,b were oxidized to give a complex reaction mixture containing 4-pyridones IVa,b.

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