Microwave irradiated synthesis of 2-bromo(chloro)indoles via intramolecular cyclization of 2-(gem-dibromo(chloro)vinyl)anilines in the presence of TBAF under metal-free conditions

RSC Advances ◽  
2014 ◽  
Vol 4 (51) ◽  
pp. 26918-26923 ◽  
Author(s):  
Min Wang ◽  
Pinhua Li ◽  
Wei Chen ◽  
Lei Wang
Keyword(s):  
Microwave Irradiation ◽  
Intramolecular Cyclization ◽  
Metal Free

2-Bromo(chloro)indoles were readily prepared through TBAF-promoted intramolecular cyclization of 2-(gem-dibromo(chloro)vinyl)anilines in excellent yields under metal-free and microwave irradiation conditions.

Visible light driven metal-free intramolecular cyclization: a facile synthesis of 3-position substituted 3,4-dihydroisoquinolin-1(2H)-one

2019 ◽  
Vol 17 (2) ◽  
pp. 380-387 ◽  
Author(s):  
Shuai Zou ◽  
Shu Geng ◽  
Lina Chen ◽  
Haitao Wang ◽  
Feng Huang
Keyword(s):  
Visible Light ◽  
Intramolecular Cyclization ◽  
Facile Synthesis ◽  
Metal Free ◽  
Visible Light Driven

Visible light driven metal-free intramolecular cyclization: a facile synthesis of 3-position substituted 3,4-dihydroisoquinolin-1(2H)-one.

Organophosphane-Catalyzed Construction of Functionalized 2-Ylideneoxindoles via Direct β-Acylation

Synthesis ◽  
2021 ◽  
Author(s):  
Wey-Chyng Jeng ◽  
Po-Chung Chien ◽  
Sandip Sambhaji Vagh ◽  
Athukuri Edukondalu ◽  
Wenwei Lin
Keyword(s):  
Intramolecular Cyclization ◽  
Efficient Method ◽  
Bond Cleavage ◽  
Scale Up ◽  
Acyl Chlorides ◽  
Metal Free ◽  
Mild Conditions ◽  
Synthetic Utility ◽  
Mechanistic Investigations ◽  
Synthetic Transformations

We report an efficient method for the direct β-acylation of 2-ylideneoxindoles with acyl chlorides in the presence of base-catalyzed by organophosphanes. A variety of functionalized 2-ylideneoxindoles were prepared in moderate to good yields under metal-free and mild conditions via a tandem phospha-Michael/O-acylation/intramolecular cyclization/ rearrangement sequence. The mechanistic investigations revealed that the C-O bond cleavage on possible betaine intermediate is the key step for the installation of keto-functionality at β-position of 2-ylideneoxindoles in a highly stereospecific manner. The synthetic utility of this protocol could also be proven by scale-up reactions and synthetic transformations of the products.

Iodine-mediated C–N and C–S bond formation: regioselective synthesis of benzo[4,5]imidazo[2,1-b]thiazoles

2017 ◽  
Vol 41 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Sethurajan Ambethkar ◽  
Muthalu Vellimalai ◽  
Vediappen Padmini ◽  
Nattamai Bhuvanesh
Keyword(s):  
Reaction Time ◽  
Intramolecular Cyclization ◽  
Simple Procedure ◽  
Bond Formation ◽  
Molecular Iodine ◽  
Regioselective Synthesis ◽  
Thiazole Derivatives ◽  
Short Reaction Time ◽  
Metal Free

The regioselective synthesis of benzo[4,5]imidazo[2,1-b]thiazole derivatives via amination (C–N) and intramolecular cyclization (C–S) reactions in the presence of molecular iodine has been reported. This method is base and metal free and features inexpensive catalysts, with a simple procedure and a short reaction time.

scholarly journals A Convenient Metal-Free Synthesis of (E)-3-Styrylisocoumarins through Annulation of (E)-1,4-Diarylenynes

Synthesis ◽  
2016 ◽  
Vol 48 (19) ◽  
pp. 3382-3392 ◽  
Author(s):  
Guangkuan Zhao ◽  
Ling-Zhi Yuan ◽  
Mylène Roudier ◽  
Jean-François Peyrat ◽  
Abdallah Hamze ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Catalytic Amount ◽  
Metal Free ◽  
Toluenesulfonic Acid

A metal-free procedure for the cyclization of (E)-1,4-di­arylenynes is described. The reaction is promoted by a catalytic amount of p-toluenesulfonic acid and takes place in ethanol at 160 °C under microwave irradiation to afford stereoselectively (E)-3-styrylisocoumarins in good to excellent yields.

Reactions of Methyl Ketones and (Hetero)arylcarboxamides with N,N-Dimethylacetamide Dimethyl Acetal. A Simple Metal-Free Synthesis of 2,4,6-Trisubstituted Pyridines

2015 ◽  
Vol 68 (2) ◽  
pp. 184 ◽  
Author(s):  
Benjamin Prek ◽  
Uroš Grošelj ◽  
Marta Kasunič ◽  
Silvo Zupančič ◽  
Jurij Svete ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Single Crystal ◽  
Ammonium Acetate ◽  
Dimethyl Acetal ◽  
Methyl Ketones ◽  
Closed Vessel ◽  
Simple Metal ◽  
One Pot ◽  
X Ray ◽  
Metal Free

Two metal-free syntheses of 2,4,6-trisubstituted pyridines 10a–m and 16a–j are described. N,N,6-Trimethyl-4-(substituted)pyridin-2-amines 10 were prepared from aryl or heteroaryl methyl ketones which were transformed with N,N-dimethylacetamide dimethyl acetal (DMADMA) into enaminones 4a–m, followed by treatment with ammonium acetate to give (Z)-3-amino-1-(substituted)but-2-en-1-ones 5a–m. These were treated with DMADMA under microwave irradiation in a closed vessel at 130°C, to give via intermediates 7–9 the final products 10a–m. N2,N2,N4,N4-Tetramethyl-6-(substituted) pyridine-2,4-diamines 16a–j were prepared in a one-pot synthesis from the corresponding carboxamides 11a–j by treatment with an excess of DMADMA in a closed vessel under microwave irradiation to give via intermediates 12a–j to 15a–j the final products 16a–j. X-Ray single crystal diffractometry studies of the enaminones 5c, 5g, 5i, 5j, and 5m and 2,4,6-trisubstituted pyridines 16a, 16b, 16g, 16i, and 16j were consistent with the expected structures.

Access to Furo[2,3‐ b ]pyridines by Transition‐Metal‐Free Intramolecular Cyclization of C3‐substituted Pyridine N ‐oxides

2018 ◽  
Vol 7 (5) ◽  
pp. 879-882 ◽  
Author(s):  
Dong Wang ◽  
Meng Shen ◽  
Yuxi Wang ◽  
Jianyong Hu ◽  
Junjie Zhao ◽  
...  
Keyword(s):  
Transition Metal ◽  
Intramolecular Cyclization ◽  
Metal Free

Synthesis of Imidazo[1,5-a]quinolines via Metal-Free Oxidative Amination of sp3 C–H Bonds

Synthesis ◽  
2018 ◽  
Vol 50 (14) ◽  
pp. 2761-2767 ◽  
Author(s):  
Chen Ma ◽  
Huanhuan Liu ◽  
Xinfeng Wang
Keyword(s):  
Amino Acids ◽  
Transition Metal ◽  
Intramolecular Cyclization ◽  
Efficient Synthesis ◽  
Oxidative Amination ◽  
Metal Free ◽  
Oxidation System

A novel oxidative amination of sp3 C–H bonds was developed for the efficient synthesis of imidazo[1,5-a]quinolines from readily available α-amino acids and (2-azaaryl)methanes. This domino protocol, which was established in a TBAI-TBHP oxidation system, includes transition-metal-free decarboxylation and intramolecular cyclization. This method represented a new avenue for the synthesis of N-heterocycles using 2-methylquinolines as the synthon of quinoline-2-carbaldehydes.

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