Enantioselective Organocatalytic Michael Addition and Ring Closure Cascade Reaction of o ‐Quinone Methides with Nitriles

2020 ◽  
Vol 41 (5) ◽  
pp. 570-573 ◽  
Author(s):  
Jin Wha Park ◽  
Subin Jang ◽  
Mi Hyeon Choo ◽  
Dae Young Kim
Keyword(s):  
Michael Addition ◽  
Cascade Reaction ◽  
Ring Closure ◽  
Quinone Methides

Organocatalytic Enantioselective 1,6-aza -Michael Addition of Isoxazolin-5-ones to p -Quinone Methides

2020 ◽  
Vol 2020 (5) ◽  
pp. 627-630 ◽  
Author(s):  
Ricardo Torán ◽  
Carlos Vila ◽  
Amparo Sanz-Marco ◽  
M. Carmen Muñoz ◽  
José R. Pedro ◽  
...  
Keyword(s):  
Michael Addition ◽  
Quinone Methides

Catalyst-Free One-Pot Synthesis of Novel Heteroarylamine Substituted Furo[3,2-c]coumarins

Synlett ◽  
2018 ◽  
Vol 29 (12) ◽  
pp. 1589-1592 ◽  
Author(s):  
Abolfazl Olyaei ◽  
Mahnaz Saraei ◽  
Reyhaneh Khoeiniha
Keyword(s):  
Michael Addition ◽  
Aldol Condensation ◽  
Ring Closure ◽  
Dehydration Reaction ◽  
One Pot ◽  
Catalyst Free ◽  
One Pot Synthesis ◽  
Tandem Process ◽  
First Time

A high-yielding cyclocondensation of 4-hydroxycoumarin, phenylglyoxal monohydrate, and heteroarylamines proceeds without catalysis, which gives novel functionalized furo[3,2-c]coumarins and heteroarylamino alkylation of coumarin products in acetonitrile under reflux, is reported for the first time. This tandem process involves sequentially an aldol condensation, Michael addition, a ring closure, and dehydration reaction.

Uncatalyzed diastereoselective synthesis of alkyliminofurochromone-derived benzylmalononitriles via a three-component cascade reaction: competition between Diels–Alder cycloaddition and Michael addition

2021 ◽  
Author(s):  
Mohammad Bagher Teimouri ◽  
Zahra Mokhtare ◽  
Hamid Reza Khavasi
Keyword(s):  
Michael Addition ◽  
Heterocyclic Ring ◽  
Cascade Reaction ◽  
Diels Alder ◽  
Chemical Bonds ◽  
Diastereoselective Synthesis ◽  
Atom Economy ◽  
One Pot

Three new chemical bonds and three stereogenic centres and one heterocyclic ring were assembled stereoselectively in a convenient high atom-economy one-pot operation.

scholarly journals A study of the sequential Michael addition-ring closure reaction of ethyl acetoacetate with chalcone: influence of quaternary ammonium cations as phase transfer catalysts

2005 ◽  
Vol 16 (5) ◽  
pp. 1048-1053
Author(s):  
Regina C. V. Lopes ◽  
Maria da Conceição F. de Oliveira ◽  
Telma L. G. de Lemos ◽  
Marcos C. de Mattos
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Ethyl Acetoacetate ◽  
Phase Transfer ◽  
Ring Closure ◽  
Phase Transfer Catalysts ◽  
Quaternary Ammonium Cations

A Highly Efficient Synthesis of Lamellarins K and L by the Michael Addition/Ring-Closure Reaction of Benzyldihydroisoquinoline Derivatives with Ethoxycarbonyl-β-nitrostyrenes

2004 ◽  
Vol 116 (7) ◽  
pp. 884-886 ◽  
Author(s):  
Poonsakdi Ploypradith ◽  
Chulabhorn Mahidol ◽  
Poolsak Sahakitpichan ◽  
Siriporn Wongbundit ◽  
Somsak Ruchirawat
Keyword(s):  
Michael Addition ◽  
Ring Closure ◽  
Efficient Synthesis ◽  
Highly Efficient ◽  
The Michael Addition

Solvolysis and ring closure of quinone methides photogenerated from biaryl systems

2005 ◽  
Vol 83 (9) ◽  
pp. 1306-1323 ◽  
Author(s):  
Yijian Shi ◽  
Peter Wan
Keyword(s):  
Ring Closure ◽  
Quinone Methide ◽  
High Yield ◽  
Nanosecond Laser ◽  
Quinone Methides ◽  
Molecular Mechanics Calculations ◽  
Fluorescence Studies ◽  
Long Wavelength ◽  
Thermal Chemistry ◽  
Nanosecond Laser Photolysis

A variety of biaryl quinone methides have been photogenerated with a range of efficiencies from biaryl precursors 4–6 and 8, 10, and 11, all having hydroxyl and hydroxymethyl substituents on alternate rings. These novel biaryl quinone methides, which cannot be readily generated via thermal chemistry, are trapped by added nucleophiles such as MeOH and ethanolamine; two that cannot undergo electrocyclic ring closure (from 8 and 11) are readily observable by nanosecond laser photolysis, with long wavelength maxima (λmax) of 600 and 520 nm, respectively. Photogenerated o,o′-biaryl quinone methides undergo electrocyclic ring closure to give the corresponding chromene (pyran) products in high yield. Since the precursor biaryl alcohols have highly twisted structures in the ground state (dihedral angle of up to 90° by molecular mechanics calculations), a significant twisting motion to planarity is required to achieve reaction. Using steady-state fluorescence studies, we present evidence to suggest that the mechanism of quinone methide formation may occur via one of the following mechanisms: (i) dissociation of the proton from ArOH that precedes twisting; or (ii) ArOH dissociation and twisting taking place either simultaneously or in quick succession.Key words: biaryl quinone methide, photosolvolysis, photodeprotonation, photocyclization.

Asymmetric synthesis of highly functionalized spirothiazolidinone tetrahydroquinolines via a squaramide-catalyzed cascade reaction

2018 ◽  
Vol 16 (48) ◽  
pp. 9390-9401 ◽  
Author(s):  
Yong-Xing Song ◽  
Da-Ming Du
Keyword(s):  
Asymmetric Synthesis ◽  
Michael Addition ◽  
Addition Reaction ◽  
Cascade Reaction ◽  
Michael Addition Reaction

A bifunctional squaramide-catalyzed asymmetric cascade aza-Michael/Michael addition reaction for the synthesis of chiral spirothiazolidinone tetrahydroquinolines with three contiguous stereocenters has been developed.

A Cascade Reaction of Michael Addition and Truce-Smiles Rearrangement to Synthesize Trisubstituted 4-Quinolone Derivatives

2020 ◽  
Vol 85 (23) ◽  
pp. 14937-14944
Author(s):  
Caixia Xie ◽  
Di Yang ◽  
Xinfeng Wang ◽  
Chen Ma
Keyword(s):  
Michael Addition ◽  
Cascade Reaction ◽  
Smiles Rearrangement ◽  
Quinolone Derivatives

Asymmetric Organocatalytic Michael Addition–Cyclization Cascade of Cyclopentane-1,2-dione with Substituted α,β-Unsaturated Aldehydes

Synthesis ◽  
2017 ◽  
Vol 49 (14) ◽  
pp. 3118-3125 ◽  
Author(s):  
Margus Lopp ◽  
Gert Preegel ◽  
Estelle Silm ◽  
Sandra Kaabel ◽  
Ivar Järving ◽  
...  
Keyword(s):  
Michael Addition ◽  
Cascade Reaction ◽  
One Pot ◽  
Unsaturated Aldehydes ◽  
Michael Acceptors

An asymmetric organocatalytic Michael addition–cyclization cascade reaction has been developed using cyclopentane-1,2-dione as a Michael donor and α,β-unsaturated aldehydes as Michael acceptors. Bicyclic hemiacetals were obtained in excellent yields and enantioselectivities. On the basis of the results, a one-pot reaction has been developed to obtain chiral 3-substituted cyclopentane-1,2-diones and substituted dihydropyrans in good yields and excellent enantioselectivity.

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