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.

Synthesis of Malononitrile-Substituted Diarylmethines via 1,6-Addition of Masked Acyl Cyanides to para-Quinone Methides

Synthesis ◽  
2017 ◽  
Vol 50 (04) ◽  
pp. 872-880 ◽  
Author(s):  
Dieter Enders ◽  
Kun Zhao ◽  
Ying Zhi ◽  
Ai Wang
Keyword(s):  
Bioactive Compounds ◽  
Efficient Method ◽  
Conjugate Addition ◽  
Quinone Methides ◽  
Mild Conditions ◽  
Synthetic Utility

An efficient method for the synthesis of malononitrile-substituted­ diarylmethines through 1,6-conjugate addition of para-quinone­ methides with masked acyl cyanide (MAC) reagents has been developed. Under mild conditions, the scalable reaction occurs in good to excellent yields providing a straightforward access to a series of malononitrile-substituted diarylmethines. The synthetic utility of this protocol has been demonstrated in the synthesis of bioactive compounds.

A Mild and Efficient Synthesis of Pyrazolo[1,5-a]pyridines Mediated by PPh3/I2

Synlett ◽  
2021 ◽  
Author(s):  
Kai Jia ◽  
Wenchao Ma ◽  
Yintao Yan ◽  
Chenming Zhang ◽  
Chao Jiang
Keyword(s):  
Intramolecular Cyclization ◽  
Efficient Synthesis ◽  
Metal Free ◽  
Mild Conditions

Synthesis of 2,3-diaryl substituted pyrazolo[1,5-a]pyridines under metal-free and mild conditions in moderate to good yields is described. The intramolecular cyclization of the oxime substrates is mediated by PPh3/I2, which leads directly to pyrazolo[1,5-a]pyridines without formation of the 2H-azirine intermediate. Different substituents on the aryl rings are compatible with the method.

Metal-free n-Et4NBr-catalyzed radical cyclization of disulfides and alkynes leading to benzothiophenes under mild conditions

RSC Advances ◽  
2014 ◽  
Vol 4 (89) ◽  
pp. 48547-48553 ◽  
Author(s):  
Daoshan Yang ◽  
Kelu Yan ◽  
Wei Wei ◽  
Laijin Tian ◽  
Qinghe Li ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Bond Formation ◽  
Environmentally Friendly ◽  
Radical Cyclization ◽  
Title Reaction ◽  
Metal Free ◽  
Mild Conditions

The title reaction involves metal free TEAB-catalyzed S–S bond cleavage, C–S bond formation and C–C bond formation; it uses readily available disulfides and alkynes as substrates, and environmentally friendly TEAB as catalyst to synthesize useful benzothiophene derivatives.

Effective, transition metal free and selective C–F activation under mild conditions

RSC Advances ◽  
2015 ◽  
Vol 5 (10) ◽  
pp. 7035-7048 ◽  
Author(s):  
Xianqiang Kong ◽  
Huizi Zhang ◽  
Yunqing Xiao ◽  
Changsheng Cao ◽  
Yanhui Shi ◽  
...  
Keyword(s):  
Transition Metal ◽  
Aromatic Amines ◽  
Bond Cleavage ◽  
Metal Free ◽  
Mild Conditions

A simple and effective aromatic nucleophilic monosubstitution reaction for the synthesis of aromatic amines via selective C–F bond cleavage of various fluoroarenes with primary and secondary aromatic amines is demonstrated.

Conversion of Esters to Thioesters under Mild Conditions

2021 ◽  
Author(s):  
Yijun Shi ◽  
Xuejing Liu ◽  
Han Cao ◽  
Fusheng Bie ◽  
Ying Han ◽  
...  
Keyword(s):  
Transition Metal ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Free System ◽  
Metal Free ◽  
Mild Conditions

We report conversion of esters to thioesters via selective C–O bond cleavage/weak C–S bond formation under transition-metal-free conditions. The method is notable for a general and practical transition-metal-free system, broad...

Pyridine-mediated B-B Bond Activation of (RO)2B-B(OR)2 for Generating Borylpyridine Anions and Pyridine-stabilized Boryl Radicals as Useful Boryl Reagents in Organic Synthesis

Synthesis ◽  
2021 ◽  
Author(s):  
Luis Carlos Misal Castro ◽  
Ibrahim Sultan ◽  
Hayato Tsurugi ◽  
Kazushi Mashima
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Pyridine Derivatives ◽  
Organic Transformations ◽  
Lewis Bases ◽  
Metal Free ◽  
Synthetic Utility

Significant developments have been achieved in recent years toward the utilization of (RO)2B-B(OR)2 for exploring transition metal-free organic transformations in organic synthesis. Among the various combinations of Lewis bases with diborons developed so far, pyridine-derivatives are simple, commercially available, and cheap compounds to expand the synthetic utility of diborons by generating borylpyridine anions and pyridine-stabilized boryl radicals via the B-B bond cleavage. These borylpyridine species mediate a series of transformations in both a catalytic and stoichiometric manner for C-X activation (X = Halogen, CO2H, NR2) and concomitant C-borylation, hydroboration, C-C bond formation, and reduction reactions.

Transition-metal-free cross-coupling of thioethers with aryl(cyano)iodonium triflates: a facile and efficient method for the one-pot synthesis of thiocyanates

2015 ◽  
Vol 51 (33) ◽  
pp. 7180-7183 ◽  
Author(s):  
Dan Zhu ◽  
Denghu Chang ◽  
Lei Shi
Keyword(s):  
Transition Metal ◽  
Efficient Method ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
One Pot ◽  
Metal Free ◽  
One Pot Synthesis ◽  
One Step ◽  
The One

A novel transition-metal-free method for the one-step synthesis of thiocyanates via the C–S bond cleavage of readily available thioethers was developed.

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.

An efficient method for the preparation of tert-butyl esters from benzyl cyanide and tert-butyl hydroperoxide under the metal free condition

RSC Advances ◽  
2016 ◽  
Vol 6 (104) ◽  
pp. 102023-102027 ◽  
Author(s):  
Xiuling Chen ◽  
Yan Li ◽  
Minghu Wu ◽  
Haibing Guo ◽  
Longqiang Jiang ◽  
...  
Keyword(s):  
Efficient Method ◽  
Bond Cleavage ◽  
Bond Formation ◽  
One Pot ◽  
Free Condition ◽  
Butyl Hydroperoxide ◽  
Metal Free ◽  
Tert Butyl ◽  
Butyl Esters ◽  
Tert Butyl Hydroperoxide

A novel protocol to synthesize tert-butyl esters from benzyl cyanides and tert-butyl hydroperoxide has been successfully achieved. Csp3–H bond oxidation, C–CN bond cleavage and C–O bond formation proceeded smoothly in one pot under the metal-free condition.

Transition-metal-free direct perfluoroalkylation of quinoline amides at C5 position through radical cross-coupling under mild conditions

2017 ◽  
Vol 4 (6) ◽  
pp. 1116-1120 ◽  
Author(s):  
Jun Xu ◽  
Li Qiao ◽  
Beibei Ying ◽  
Xiaolei Zhu ◽  
Chao Shen ◽  
...  
Keyword(s):  
Transition Metal ◽  
Efficient Method ◽  
Cross Coupling ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Low Energy ◽  
Metal Free ◽  
Mild Conditions

A simple low-energy and efficient method is established for the synthesis of C5-selective perfluoroalkylation quinolines in the absence of any transition metal catalysts.

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