Transition-metal-free catalyzed [3+2] cycloadditions/oxidative aromatization reactions for the synthesis of annulated indolizines

2019 ◽  
Vol 43 (43) ◽  
pp. 17000-17003 ◽  
Author(s):  
Qianwei Zhang ◽  
Bin Wang ◽  
Huifang Ma ◽  
Keyume Ablajan
Keyword(s):  
Transition Metal ◽  
Direct Construction ◽  
Metal Free ◽  
Oxidative Aromatization

A transition-metal-free catalyzed [3+2] cycloadditions/oxidative aromatization three-component reactions for direct construction of annulated indolizines was reported.

Transition-Metal-Free Aerobic Oxidative Cross-Coupling of Indoles with Arylidenemalononitriles

Synlett ◽  
2019 ◽  
Vol 31 (02) ◽  
pp. 194-198
Author(s):  
Aizhen Yang ◽  
Zheng Li
Keyword(s):  
Transition Metal ◽  
Efficient Method ◽  
Cross Coupling ◽  
Transition Metal Catalysts ◽  
High Yield ◽  
Atom Economy ◽  
Direct Construction ◽  
Organometallic Reagents ◽  
Metal Free ◽  
Mild Conditions

An efficient method for the direct construction of C(sp2)–C(sp2) bonds by aerobic oxidative cross-coupling of indoles with arylidenemalononitriles is described. Various [aryl(1H-indol-3-yl)methylene]malononitriles were efficiently synthesized by using air as an oxidant under mild conditions. The salient features for this protocol are no transition-metal catalysts, no organometallic reagents, high atom economy, high yield, mild conditions, and simple workup procedures.

Base-Catalyzed Tandem Cyclization: Diastereoselective Access to the 3,4-Dihydroisoquinolin-2(1H)-one Core

Synthesis ◽  
2018 ◽  
Vol 51 (06) ◽  
pp. 1473-1481 ◽  
Author(s):  
Harshadas Meshram ◽  
Ravindra Kumbhare ◽  
Prashishkumar Shirsat ◽  
Navnath Khomane ◽  
Sneha Meshram ◽  
...  
Keyword(s):  
Natural Products ◽  
Transition Metal ◽  
Acetylenic Esters ◽  
One Pot ◽  
Direct Construction ◽  
Metal Free ◽  
Diastereoselective Reaction ◽  
Three Component Reaction ◽  
Tandem Cyclization

A novel, one-pot reaction for the synthesis of 3,4-dihydroisoquinolin-2(1H)-one derivatives is developed via a base-mediated three-component reaction of ninhydrin, aniline and acetylenic esters. This diastereoselective reaction takes place in methanol at 70 °C under transition-metal-free conditions, and direct construction of the C–N and C–C bonds is readily achieved via tandem cyclization. These cyclic frameworks are resourceful small molecular keys to many natural products.

Catalytic dehydrogenative aromatization of cyclohexanones and cyclohexenones

2018 ◽  
Vol 16 (45) ◽  
pp. 8662-8676 ◽  
Author(s):  
Xueli Liu ◽  
Jun Chen ◽  
Tianlin Ma
Keyword(s):  
Transition Metal ◽  
Substituted Phenols ◽  
Metal Free ◽  
Literature Reviews ◽  
Scant Attention ◽  
Oxidative Aromatization ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

Prompted by the scant attention paid by published literature reviews to the comprehensive catalytic dehydrogenative aromatization of cyclohexa(e)nones, this review describes recent methods developed to-date involving transition-metal-catalyzed oxidative aromatization and metal-free strategies for the transformation of cyclohexa(e)nones to substituted phenols.

Transition-metal-free catalytic hydroboration reduction of amides to amines

2020 ◽  
Vol 7 (21) ◽  
pp. 3515-3520
Author(s):  
Wubing Yao ◽  
Jiali Wang ◽  
Aiguo Zhong ◽  
Shiliang Wang ◽  
Yinlin Shao
Keyword(s):  
Transition Metal ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Value Added ◽  
Metal Free

The selective catalytic reduction of amides to value-added amine products is a desirable but challenging transformation.

Deaminative carbonylative thioesterification of activated alkylamines with thiophenols under transition-metal-free conditions

2021 ◽  
Author(s):  
Fengqian Zhao ◽  
Xiao-Feng Wu
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Metal Free

A transition-metal-free radical carbonylation of activated alkylamines with thiophenols has been successfully developed. Various thioesters were selectively produced with moderate to good yields.

Regioselective C3-H Trifluoromethylation of 2H-Indazole Under Transition-Metal-Free Photoredox Catalysis

2019 ◽  
Author(s):  
Arumugavel Murugan ◽  
Venkata Nagarjuna Babu ◽  
Nagaraj Sabarinathan ◽  
Sharada Duddu. S
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Practical Approach ◽  
Hypervalent Iodine ◽  
Radical Mechanism ◽  
Photoredox Catalysis ◽  
Metal Free

Here we report a visible-light-promoted metal-free regioselective C3-H trifluoromehtylation reaction that proceeds via radical mechanism and which supported by control experiments. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the present trifluoromethylation reaction and synthesis of a library of trifluoromethylated indazoles.

Selective Oxidation of Alcohols Catalyzed by a Transition Metal-Free System of NHPI/DDQ/NaNO2

2011 ◽  
Vol 32 (1) ◽  
pp. 118-122 ◽  
Author(s):  
Lipeng ZHOU ◽  
Chaofeng ZHANG ◽  
Tao FANG ◽  
Bingbing ZHANG ◽  
Ying WANG ◽  
...  
Keyword(s):  
Transition Metal ◽  
Selective Oxidation ◽  
Free System ◽  
Metal Free ◽  
Oxidation Of Alcohols

Defect engineering and characterization of active sites for efficient electrocatalysis

Nanoscale ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 3327-3345
Author(s):  
Xuecheng Yan ◽  
Linzhou Zhuang ◽  
Zhonghua Zhu ◽  
Xiangdong Yao
Keyword(s):  
Transition Metal ◽  
Active Sites ◽  
Defect Engineering ◽  
Metal Free

This review highlights recent advancements in defect engineering and characterization of both metal-free carbons and transition metal-based electrocatalysts.

Transition metal free, green and facile halogenation of ketene dithioacetals using a KX–oxidant system

2021 ◽  
Author(s):  
Vishakha Rai ◽  
Ganesh Shivayogappa Sorabad ◽  
Mahagundappa Rachappa Maddani
Keyword(s):  
Transition Metal ◽  
Ambient Temperature ◽  
Metal Free ◽  
Ketene Dithioacetals ◽  
System P ◽  
Oxidative Halogenation ◽  
Potassium Halide

A facile oxidative halogenation of α-oxo ketene dithioacetals is achieved by using a potassium halide and an oxidant combination under transition metal free conditions at ambient temperature.

Highly chemoselective deoxygenation of N-heterocyclic N-oxides under transition metal-free conditions

2021 ◽  
Vol 19 (16) ◽  
pp. 3735-3742
Author(s):  
Se Hyun Kim ◽  
Ju Hyeon An ◽  
Jun Hee Lee
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Eosin Y ◽  
Metal Free ◽  
Simple Protocol

Here, we provide an operationally simple protocol for the highly chemoselective deoxygenation of various functionalized N-heterocyclic N-oxides under visible light-mediated photoredox conditions with Na2-eosin Y as an organophotocatalyst.

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