Asymmetric Cyclization Reactions of Allenoates with Imines or α,β-Unsaturated Ketones Catalyzed by Organocatalysts Derived from Cinchona Alkaloids

2012 ◽  
Vol 18 (22) ◽  
pp. 6712-6716 ◽  
Author(s):  
Cheng-Kui Pei ◽  
Min Shi
Keyword(s):  
Cinchona Alkaloids ◽  
Cyclization Reactions ◽  
Unsaturated Ketones

scholarly journals A Remarkably Efficient Phase-Transfer Catalyzed Amination of α-Bromo-α, β-Unsaturated Ketones in Water

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Alemayehu Mekonnen ◽  
Alemu Tesfaye
Keyword(s):  
Quaternary Ammonium ◽  
Phase Transfer ◽  
Conjugate Addition ◽  
Quaternary Ammonium Salts ◽  
Cinchona Alkaloids ◽  
Ammonium Salts ◽  
Alkylation Reaction ◽  
Pt Catalysts ◽  
Unsaturated Ketones ◽  
Catalytic Performances

Tandem conjugate addition–alkylation reaction of various amines with α-bromo-α, β-unsaturated ketones resulted in near-quantitative conversions into the corresponding aziridines when the reaction was carried out in the presence of 10 mol% of phase-transfer, PT catalysts in water. Some chiral quaternary ammonium salts derived from Cinchona alkaloids were investigated as water-stable PT catalysts. The scope and limitations of the reaction have also been investigated. The catalytic performances were significantly improved in comparison with the corresponding ordinary quaternary ammonium salt catalysts, and excellent yields (81%–96%) were obtained. Although an increase in the rate of aziridination has been accomplished, no stereoselectivity was observed. The positive values of the protocol have been confirmed.

Catalytic enantioselective cascade Michael/cyclization reaction of 3-isothiocyanato oxindoles with exocyclic α,β-unsaturated ketones en route to 3,2′-pyrrolidinyl bispirooxindoles

2016 ◽  
Vol 14 (43) ◽  
pp. 10175-10179 ◽  
Author(s):  
Satavisha Kayal ◽  
Santanu Mukherjee
Keyword(s):  
Cyclization Reaction ◽  
Cyclization Reactions ◽  
Unsaturated Ketones ◽  
Tertiary Amino

Cascade Michael/cyclization reactions between 3-isothiocyanato oxindoles and exocyclic α,β-unsaturated ketones are shown to proceed in the presence of a tertiary amino-squaramide catalyst and furnish 3,2′-pyrrolidinyl bispirooxindoles with excellent enantioselectivities (up to 99 : 1 er).

Ultrasonic assisted dimeric cinchona based chiral phase transfer catalysts for highly enanatioselective synthesis of epoxidation of α,β-unsaturated ketones

RSC Advances ◽  
2014 ◽  
Vol 4 (104) ◽  
pp. 60293-60299 ◽  
Author(s):  
Jayaraman Sivamani ◽  
Veeramanoharan Ashokkumar ◽  
Velu Sadhasivam ◽  
Kumaraguru Duraimurugan ◽  
Ayyanar Siva
Keyword(s):  
Ultrasonic Irradiation ◽  
Phase Transfer ◽  
Cinchona Alkaloids ◽  
Ammonium Bromide ◽  
Chiral Phase ◽  
Unsaturated Ketones ◽  
Phase Transfer Catalysts ◽  
Ultrasonic Assisted ◽  
Chiral Phase Transfer Catalysts ◽  
Enantioselective Epoxidation

New types of bis-quaternary ammonium bromide as chiral multisite phase transfer catalysts derived from cinchona alkaloids have been developed and evaluated for the enantioselective epoxidation of chalcones in the presence of lower concentrations of various oxidants, bases and ultrasonic irradiation conditions.

Synthesis and cyclization reactions with pyrazolopyrimidinyl keto esters part I. Reactivity of pyrazolopyrimidinyl β-keto ester and pyrazolopyrimidinyl α,β-unsaturated ketones

2006 ◽  
Vol 60 (5) ◽  
Author(s):  
M. Awas
Keyword(s):  
Spectral Analysis ◽  
Biological Activity ◽  
Chemical Transformations ◽  
Cyclization Reactions ◽  
Keto Ester ◽  
Unsaturated Ketones ◽  
Keto Esters ◽  
Chemical Behaviour ◽  
Derivatives Of

Abstract5-Acetyl-4,5-dihydro-1-phenylpyrazolo[3,4-d]pyrimidin-4-one was prepared and subjected to various chemical transformations to give novel 5-heterocyclic pyrazolopyrimidinone derivatives of expected important biological activity. Then, the latter compounds were used to obtain β-keto ester and α,β-unsaturated carbonylpyrazolopyrimidinones which were used as alternate precursors to produce new pyrazolopyrimidinones substituted with five-membered heterocycles such as pyrazole and isoxazole. The structure of these compounds was identified on the basis of their chemical behaviour as well as elemental and spectral analysis.

Catalytic Enantioselective Michael Addition of 1-Fluorobis(phenylsulfonyl)methane to α,β-Unsaturated Ketones Catalyzed by Cinchona Alkaloids

2008 ◽  
Vol 120 (42) ◽  
pp. 8171-8174 ◽  
Author(s):  
Tatsuya Furukawa ◽  
Norio Shibata ◽  
Satoshi Mizuta ◽  
Shuichi Nakamura ◽  
Takeshi Toru ◽  
...  
Keyword(s):  
Michael Addition ◽  
Cinchona Alkaloids ◽  
Unsaturated Ketones

ChemInform Abstract: Catalytic Enantioselective Michael Addition of 1-Fluoro-bis(phenylsulfonyl)methane to α,β-Unsaturated Ketones Catalyzed by Cinchona Alkaloids.

ChemInform ◽  
2009 ◽  
Vol 40 (7) ◽  
Author(s):  
Tatsuya Furukawa ◽  
Norio Shibata ◽  
Satoshi Mizuta ◽  
Shuichi Nakamura ◽  
Takeshi Toru ◽  
...  
Keyword(s):  
Michael Addition ◽  
Cinchona Alkaloids ◽  
Unsaturated Ketones
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