scholarly journals N–N Bond Formation between Primary Amines and Nitrosos: Direct Synthesis of 2-Substituted Indazolones with Mechanistic Insights

2018 ◽  
Vol 20 (16) ◽  
pp. 4736-4739 ◽  
Author(s):  
Jie S. Zhu ◽  
Niklas Kraemer ◽  
Marina E. Shatskikh ◽  
Clarabella J. Li ◽  
Jung-Ho Son ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Bond Formation ◽  
Primary Amines

Copper nanoparticles supported on charcoal mediated one-pot three-component synthesis of N-substituted-2H-indazoles via consecutive condensation C–N and N–N bond formation

2019 ◽  
Vol 97 (4) ◽  
pp. 303-309 ◽  
Author(s):  
Reza Khalifeh ◽  
Faranak Karimzadeh
Keyword(s):  
Copper Nanoparticles ◽  
Sodium Azide ◽  
Direct Synthesis ◽  
Bond Formation ◽  
Primary Amines ◽  
Title Reaction ◽  
One Pot

An efficient and straightforward protocol for direct synthesis of 2H-indazoles is achieved from consecutive condensation of 2-halobenzaldehydes, primary amines, and sodium azide catalyzed by heterogeneous copper nanoparticles on charcoal (Cu/C) is achieved. The recoverable heterogeneous copper nanoparticles on charcoal (Cu/C) catalyst exhibited an impressive activity for the title reaction without any additives (expensive ligands, etc.). A series of structurally diverse 2H-indazoles were prepared in good to excellent yields from easily accessible starting materials by employing this protocol.

scholarly journals Unmasked Primary Amines as C-Nucleophiles for Catalytic C–C Bond-Formation

2020 ◽  
Author(s):  
Alison Ryder ◽  
William Cunningham ◽  
George Ballantyne ◽  
Tom Mules ◽  
Anna Kinsella ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Direct Synthesis ◽  
Bond Formation ◽  
Hydrogen Atom Transfer ◽  
Primary Amines ◽  
Amino Group ◽  
Atom Economy ◽  
Critical Gap ◽  
Azide Ion

A practical, catalytic entry to α,α,α‑trisubstituted (α‑tertiary) primary amines by C–H functionalisation has long been recognised as a critical gap in the synthetic toolbox. We report a simple and scalable solution to this problem that does not require any <i>in situ</i> protection of the amino group and proceeds with 100% atom-economy. Our strategy, which uses an organic photocatalyst in combination with azide ion as a hydrogen atom transfer (HAT) catalyst, provides a direct synthesis of <i>C</i>-alkylated amines or γ‑lactams, including valuable azaspirocycles. We anticipate that this methodology will inspire new retrosynthetic disconnections for substituted amine derivatives in organic synthesis, and particularly for challenging α‑tertiary primary amines.

scholarly journals Unmasked Primary Amines as C-Nucleophiles for Catalytic C–C Bond-Formation

2020 ◽  
Author(s):  
Alison Ryder ◽  
William Cunningham ◽  
George Ballantyne ◽  
Tom Mules ◽  
Anna Kinsella ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Direct Synthesis ◽  
Bond Formation ◽  
Hydrogen Atom Transfer ◽  
Primary Amines ◽  
Amino Group ◽  
Atom Economy ◽  
Critical Gap ◽  
Azide Ion

A practical, catalytic entry to α,α,α‑trisubstituted (α‑tertiary) primary amines by C–H functionalisation has long been recognised as a critical gap in the synthetic toolbox. We report a simple and scalable solution to this problem that does not require any <i>in situ</i> protection of the amino group and proceeds with 100% atom-economy. Our strategy, which uses an organic photocatalyst in combination with azide ion as a hydrogen atom transfer (HAT) catalyst, provides a direct synthesis of <i>C</i>-alkylated amines or γ‑lactams, including valuable azaspirocycles. We anticipate that this methodology will inspire new retrosynthetic disconnections for substituted amine derivatives in organic synthesis, and particularly for challenging α‑tertiary primary amines.

α-Ketophosphonates in the Synthesis of α-iminophosphonates

2020 ◽  
Vol 7 (2) ◽  
pp. 226-238
Author(s):  
Petro P. Ony`sko ◽  
Tetyana I. Chudakova ◽  
Vladimir V. Pirozhenko ◽  
Alexandr B. Rozhenko
Keyword(s):  
Bond Cleavage ◽  
Direct Synthesis ◽  
Equilibrium Mixture ◽  
Primary Amines ◽  
Alkyl Amines ◽  
Protic Solvents ◽  
Metallic Salts ◽  
Direct Preparation ◽  
Stage Synthesis ◽  
Aprotic Dipolar Solvent

The potentialities of condensation of α-ketophosphonates with primary amines for direct synthesis of α-iminophosphonates have been revealed. Diesters of α-ketophosphonic acids react with the primary amines by two competitive pathways: with a formation of α-iminophosphonates or a C-P bond cleavage resulting in a hydrogen phosphonate and an acylated amine. In many cases, the latter undesirable pathway is dominant, especially for more nucleophilic alkyl amines. Using metallic salts of α-ketophosphonates avoids the C-P bond cleavage, allowing direct preparation of α-phosphorylated imines by the reaction with primary amines. This strategy provides an atom economy single-stage synthesis of iminophosphonates – precursors of bio relevant phosphorus analogs of α-amino acids. Methyl sodium iminophosphonates, bearing aryl or heteryl substituents at the imino carbon atom exist in solutions at room temperature as an equilibrium mixture of Z- and E-isomers. A configuration of the C=N bond can be controlled by the solvent: changing the aprotic dipolar solvent DMSO-d6 by water or alcohols leads to the change from a predominant Z-isomer to almost an exclusive E-form. In contrast, diesters of the respective iminophosphonates exist in non-protic solvents predominantly in Econfiguration. The solvent effect on E-Z stereochemistry is demonstrated by DFT calculations.

Copper-catalyzed coupling of anthranils and α-keto acids: direct synthesis of α-ketoamides

2019 ◽  
Vol 17 (24) ◽  
pp. 5902-5907 ◽  
Author(s):  
Ping-Gui Li ◽  
Hao Zhu ◽  
Min Fan ◽  
Cheng Yan ◽  
Kai Shi ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Bond Formation ◽  
Aldehyde Group ◽  
Keto Acids

Copper-catalyzed coupling of α-keto acids with anthranils is reported for the synthesis of α-ketoamides bearing an aldehyde group via N–O/C–O bond cleavages and C–N bond formation.

scholarly journals PIDA-mediated intramolecular oxidative C–N bond formation for the direct synthesis of quinoxalines from enaminones

RSC Advances ◽  
2019 ◽  
Vol 9 (14) ◽  
pp. 7718-7722 ◽  
Author(s):  
Hong Zhang ◽  
Jinhai Shen ◽  
Zhenhui Yang ◽  
Xiuling Cui
Keyword(s):  
Direct Synthesis ◽  
Bond Formation ◽  
Hypervalent Iodine ◽  
Mild Conditions

An expedient hypervalent iodine(iii)-mediated approach to obtain substituted quinoxalines from readily available enaminones has been developed under mild conditions.

Sign in / Sign up

Export Citation Format

Share Document