Regiospecific Aza-Michael Addition of 4-Aryl-1H-1,2,3-triazoles to Chalcones: Synthesis of 2,4-Disubstituted 1,2,3-Triazoles in Basic Medium

Synlett ◽  
2017 ◽  
Vol 29 (01) ◽  
pp. 99-105 ◽  
Author(s):  
Rama Peddinti ◽  
Ujjawal Bhagat
Keyword(s):  
Michael Addition ◽  
Basic Medium ◽  
Unsaturated Ketones ◽  
Metal Free ◽  
Michael Adducts ◽  
Donor Ability ◽  
High Yields

A novel metal-free and base-mediated method to display the donor ability of 1,2,3-triazoles for the synthesis of 2,4-disubstituted 1,2,3-triazoles has been developed. A DABCO-promoted aza-Michael addition of 4-aryl NH-1,2,3-triazoles to α,β-unsaturated ketones (chalcones) is presented. The reactions proceeded with complete regiospecificity in a 3:1 mixture of acetonitrile and methanol at 85 °C to provide 2,4-disubstituted 1,2,3-triazoles as Michael adducts, and the addition products 1,3-diaryl-(4-aryl-2H-1,2,3-triazol-2-yl)propan-1-ones were isolated in high yields.

Highly Enantioselective Michael Addition of Dithiomalonates to Nitroolefins Catalyzed by New Bifunctional Chiral Thioureas

Synthesis ◽  
2018 ◽  
Vol 50 (13) ◽  
pp. 2577-2586 ◽  
Author(s):  
Jia-Ni Yuan ◽  
Hui-Xia Liu ◽  
Qin-Qin Tian ◽  
Nan Ji ◽  
Kuo Shen ◽  
...  
Keyword(s):  
Michael Addition ◽  
Mild Conditions ◽  
Highly Efficient ◽  
Michael Adducts ◽  
Asymmetric Michael Addition ◽  
High Yields

We report a highly efficient asymmetric Michael addition of dithiomalonates to trans-β-nitroolefins catalyzed by versatile cinchona-based bifunctional thioureas, which provides the corresponding adducts in high yields (up to 92%) and with excellent enantioselectivities (up to 99% ee) under mild conditions. Replacement of the catalyst with its pseudo-enantiomer gives the Michael adducts with opposite configuration in similar yields and enantioselectivities.

Straightforward route to γ-sultams via novel SN/Michael addition tandem

Synthesis ◽  
2020 ◽  
Author(s):  
Anastasiia Klochkova ◽  
Andrey Bubyrev ◽  
Dmitrii Viktorovich Dar'in ◽  
Olga Yu. Bakulina ◽  
Mikhail Krasavin ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Michael Addition ◽  
X Ray ◽  
Metal Free ◽  
X Ray Crystallography ◽  
High Yields

A novel tandem approach to trisubstituted γ-sultams has been developed involving N-alkylation of methanesulfonanilides with EWG-substituted allyl bromides followed by intramolecular Michael addition. A series of various isothiazolidine 1,1-dioxides has been prepared under mild transition metal-free conditions in high yields and trans-diastereoselectivity (confirmed by X-ray crystallography). The dependence of reactivity on electronic properties of substrates has been investigated.

Novel Brønsted Acidic Ionic Liquids Based on Benzimidazolium Cation: Synthesis and Catalyzed Conjugate Addition of Indoles with α,β-unsaturated Ketones

2011 ◽  
Vol 233-235 ◽  
pp. 977-984
Author(s):  
Bin Wang ◽  
Chen Jiang Liu
Keyword(s):  
Ionic Liquids ◽  
Michael Addition ◽  
Addition Reaction ◽  
Conjugate Addition ◽  
Michael Addition Reaction ◽  
Unsaturated Ketones ◽  
Mild Conditions ◽  
Acidic Ionic Liquids ◽  
High Yields ◽  
The Michael Addition

Brønsted acidic ionic liquids based on benzimidazolium cation was synthesized and employed as an efficient catalysts for the Michael addition reaction of indoles to α,β-unsaturated ketones under mild conditions to afford the corresponding conjugate addition products in high yields (90%-98%). The catalyst 1-butyl-3-(3-sulfopropyl)benzimidazolium p-toluenesulfonate ([PSbbim][p-CH3PhSO3]) could be reused at least three times without a noticeably decrease in its activity.

One-pot metal-free synthesis of highly substituted pyrroles from 2-acetyl-3-methylene-1,4-dicarbonyl compounds and primary amines via TBHP and activated carbon oxidative aromatization of dihydropyrrole

RSC Advances ◽  
2014 ◽  
Vol 4 (29) ◽  
pp. 15007-15010 ◽  
Author(s):  
Wei Yang ◽  
Yu Zhou ◽  
Haifeng Sun ◽  
Lei Zhang ◽  
Fei Zhao ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Michael Addition ◽  
Primary Amines ◽  
Cascade Process ◽  
One Pot ◽  
Metal Free ◽  
Oxidative Aromatization ◽  
Substituted Pyrroles ◽  
Substrate Tolerance ◽  
High Yields

A metal-free cascade process for the synthesis of highly substituted pyrroles with high yields and broad substrate tolerance via enamine, aza-Michael addition and TBHP, activated carbon oxidative aromatization is reported.

High-quality oligo-RNA synthesis using the new 2′-O-TEM protecting group by selectively quenching the addition of p-tolyl vinyl sulphone to exocyclic amino functions

2007 ◽  
Vol 85 (4) ◽  
pp. 293-301 ◽  
Author(s):  
Chuanzheng Zhou ◽  
Wimal Pathmasiri ◽  
Dmytro Honcharenko ◽  
Subhrangsu Chatterjee ◽  
Jharna Barman ◽  
...  
Keyword(s):  
Michael Addition ◽  
Chemical Biology ◽  
Rna Synthesis ◽  
Spectroscopic Analysis ◽  
Multiple Bond ◽  
Protecting Group ◽  
High Quality ◽  
Heteronuclear Multiple Bond Correlation ◽  
Michael Adducts

During the F–-promoted deprotection of the oligo–RNA, synthesized using our 2′-O-(4-tolylsulfonyl)ethoxymethyl (2′-O-TEM) group [Org. Biomol. Chem. 5, 333 (2007)], p-tolyl vinyl sulphone (TVS) is formed as a by-product. The TVS formed has been shown to react with the exocyclic amino functions of adenosine (A), guanosine (G), and cytidine (C) of the fully deprotected oligo–RNA to give undesirable adducts, which are then purified by HPLC and unambiguously characterized by 1H, 13C Heteronuclear Multiple Bond Correlation (HMBC) NMR and mass spectroscopic analysis. The relative nucleophilic reactivities of the nucleobases toward TVS have been found to be the following: N6–A > N4–C > N2–G > > N3–U. This reactivity of TVS toward RNA nucleobases to give various Michael adducts could, however, be suppressed by using various amines as scavengers. Among all these amines, morpholine and piperidine are the most efficient scavenger for TVS, which gave highly pure oligo–RNA even in the crude form and can be used directly in RNA chemical biology studies.Key words: RNA synthesis, RNA alkylation, p-tolyl vinyl sulphone, Michael addition.

Highly enantioselective aza-Michael addition reactions of 4-nitrophthalimide with α,β-unsaturated ketones

RSC Advances ◽  
2013 ◽  
Vol 3 (29) ◽  
pp. 11498 ◽  
Author(s):  
Shijun Ma ◽  
Lulu Wu ◽  
Ming Liu ◽  
Xiufang Xu ◽  
Yaodong Huang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Addition Reactions ◽  
Unsaturated Ketones

scholarly journals Enantioselective synthesis of seven-membered carbo- and heterocyles by organocatalyzed intramolecular Michael addition

RSC Advances ◽  
2016 ◽  
Vol 6 (36) ◽  
pp. 30166-30169 ◽  
Author(s):  
James O. Guevara-Pulido ◽  
José M. Andrés ◽  
Deisy P. Ávila ◽  
Rafael Pedrosa
Keyword(s):  
Michael Addition ◽  
Enantioselective Synthesis ◽  
High Yields

Enantioenriched seven membered rings have been prepared in high yields and stereoselectivities by intramolecular Michael addition of functionalized enals catalyzed by Jorgensen–Hayashi catalyst.

Regioselective 1,4-conjugate aza-Michael addition of dienones with benzotriazole

2017 ◽  
Vol 23 (4) ◽  
Author(s):  
Zheng Li ◽  
Tianpeng Li ◽  
Rugang Fu ◽  
Jingya Yang
Keyword(s):  
Transition Metal ◽  
Michael Addition ◽  
Potassium Acetate ◽  
High Yield ◽  
Metal Free ◽  
Mild Conditions

AbstractThe regioselective 1,4-conjugate aza-Michael addition of dienones with benzotriazole catalyzed by potassium acetate is described. A series of 3-(benzotriazol-1-yl)-1,5-diarylpent-4-en-1-ones were efficiently synthesized under mild conditions. This protocol has advantages of transition-metal free catalyst, high yield and high regioselectivity.

Facile Synthesis of 2-Arylindoles through Plancher-Type Rearrangement of 3-Alkyl-3-Arylindolenines

Synlett ◽  
2017 ◽  
Vol 28 (15) ◽  
pp. 1994-1999
Author(s):  
Santhosh Chittimalla ◽  
Chennakesavulu Bandi ◽  
Vinod Gadi ◽  
Siva Gunturu
Keyword(s):  
Michael Addition ◽  
Facile Synthesis ◽  
Type C ◽  
High Yields

3-Alkylindoles on reaction with a cyclohexa-2,4-dien-1-one catalyzed by BF3·OEt2 gave the corresponding 3-alkyl-3-arylindolenines in high yields through a tandem Michael addition/aromatization sequence. In the presence of HCl, these indolenine derivatives underwent a facile Plancher-type C-3 to C-2 aryl rearrangement to deliver the corresponding 2-arylindoles.

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