The [4 + 2] cyclization/retro-Mannich reaction cascade of para-quinone methide derivatives with Pd-containing 1,4-dipoles

2018 ◽  
Vol 16 (37) ◽  
pp. 8395-8402 ◽  
Author(s):  
Xiao-Li Jiang ◽  
Shu-Fang Wu ◽  
Jin-Rong Wang ◽  
Han Lu ◽  
Guang-Jian Mei ◽  
...  
Keyword(s):  
Mannich Reaction ◽  
Quinone Methide ◽  
Quinone Methides

The first [4 + 2] cyclization/retro-Mannich reaction cascade of para-quinone methides with Pd-containing 1,4-dipoles generated in situ from vinyl benzoxazinanones has been established. The corresponding rearrangement products were obtained in generally good yields.

scholarly journals Asymmetric synthesis of chromene skeletons via organocatalytic domino reactions of in situ generated ortho-quinone methide with malononitrile and β-functionalized ketone

RSC Advances ◽  
2017 ◽  
Vol 7 (62) ◽  
pp. 39216-39220 ◽  
Author(s):  
Lili Zhang ◽  
Xiao Zhou ◽  
Pengfei Li ◽  
Zhantao Liu ◽  
Yang Liu ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Quinone Methide ◽  
Domino Reactions ◽  
Quinone Methides ◽  
High Yields

Enantioselective organocatalytic domino reactions of in situ generated ortho-quinone methides with malononitrile and β-functionalized ketones have been developed. This strategy could generate various chiral chromenes in high yields and stereoselectivities.

A new dehydrogenative [4 + 1] annulation between para-quinone methides (p-QMs) and iodonium ylides for the synthesis of 2,3-dihydrobenzofurans

2018 ◽  
Vol 5 (23) ◽  
pp. 3483-3487 ◽  
Author(s):  
Yan-Jie Xiong ◽  
Shao-Qing Shi ◽  
Wen-Juan Hao ◽  
Shu-Jiang Tu ◽  
Bo Jiang
Keyword(s):  
Quinone Methide ◽  
Quinone Methides ◽  
Iodonium Ylides

A new dehydrogenative [4 + 1] annulation of para-quinone methides (p-QMs) with acyclic and cyclic iodonium ylides has been established, delivering a variety of functionalized 2,3-dihydrobenzofurans with the retention of the quinone methide unit in generally good yields.

Lewis acid-catalyzed tandem cyclization of in situ generated o-quinone methides and arylsulfonyl hydrazides for a one-pot entry to 3-sulfonylbenzofurans

2019 ◽  
Vol 6 (24) ◽  
pp. 3929-3933 ◽  
Author(s):  
Fan-Xiao Meng ◽  
Ruo-Nan Wang ◽  
Hong-Li Huang ◽  
Shu-Wen Gong ◽  
Qian-Li Li ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Quinone Methides ◽  
One Pot ◽  
Acid Catalyzed ◽  
Tandem Cyclization ◽  
First Time

Lewis acid-mediated one-pot tandem cyclization of o-QMs with arylsulfonyl hydrazides was described for the first time and the corresponding 3-sulfonylbenzofuran products were obtained in moderate to good yields.

scholarly journals Asymmetric Synthesis of 2,3-Dihydrobenzofurans by a [4+1] Annulation Between Ammonium Ylides and In Situ Generated o -Quinone Methides

2017 ◽  
Vol 23 (21) ◽  
pp. 5137-5142 ◽  
Author(s):  
Nicole Meisinger ◽  
Lukas Roiser ◽  
Uwe Monkowius ◽  
Markus Himmelsbach ◽  
Raphaël Robiette ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Quinone Methides

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.

[4+n] Annulation Reactions Using ortho-Halomethyl Anilines as Aza-ortho-Quinone Methide Precursors

Synthesis ◽  
2021 ◽  
Author(s):  
Xiao-Yu He ◽  
Yu-Hong Ma ◽  
Qing-Qing Yang ◽  
Wen-Jing Xiao
Keyword(s):  
Convenient Method ◽  
Reactive Intermediates ◽  
Quinone Methide ◽  
Synthetic Chemistry ◽  
Important Class ◽  
Quinone Methides ◽  
Aniline Derivatives

Aza-ortho-quinone methides are an important class of reactive intermediates, which have found broad applications in synthetic chemistry. Recently, 1,4-elimination of ortho-halomethyl aniline derivatives has emerged as a new powerful and convenient method for aza-ortho-quinone methide generation. This review will highlight their recent applications as aza-ortho-quinone methide precursors in annulation reactions to access various biologically important nitrogen-containing heterocycles. The general mechanisms are briefly discussed as well.

Moving Past Quinone-Methides: Recent Advances toward Minimizing Electrophilic Byproducts from COS/H2S Donors

2021 ◽  
Vol 21 ◽  
Author(s):  
Michael Pluth
Keyword(s):  
Hydrogen Sulfide ◽  
Carbonic Anhydrase ◽  
Therapeutic Potential ◽  
Carbonyl Sulfide ◽  
Quinone Methide ◽  
Quinone Methides ◽  
On Demand ◽  
Physiological Processes ◽  
Recent Approach ◽  
Alternative Approaches

: Hydrogen sulfide (H2S) is an important biomolecule that plays key signaling and protective roles in different physiological processes. With the goals of advancing both the available research tools and the associated therapeutic potential of H2S, researchers have developed different methods to deliver H2S on-demand in different biological contexts. A recent approach to develop such donors has been to design compounds that release carbonyl sulfide (COS), which is quickly converted to H2S in biological systems by the ubiquitous enzyme carbonic anhydrase (CA). Although highly diversifiable, many approaches using this general platform release quinone methides or related electrophiles after donor activation. Many such electrophiles are likely scavenged by water, but recent efforts have also expanded alternative approaches that minimize the formation of electrophilic byproducts generated after COS release. This mini-review focuses specifically on recent examples of COS-based H2S donors that do not generate quinone methide byproducts after donor activation.

scholarly journals Correction: An organic-base catalyzed asymmetric 1,4-addition of tritylthiol to in situ generated aza-o-quinone methides at the H2O/DCM interface

2019 ◽  
Vol 55 (64) ◽  
pp. 9567-9567
Author(s):  
Xianghui Liu ◽  
Kai Wang ◽  
Wengang Guo ◽  
Yan Liu ◽  
Can Li
Keyword(s):  
Organic Base ◽  
Quinone Methides

Correction for ‘An organic-base catalyzed asymmetric 1,4-addition of tritylthiol to in situ generated aza-o-quinone methides at the H2O/DCM interface’ by Xianghui Liu et al., Chem. Commun., 2019, 55, 2668–2671.

Sign in / Sign up

Export Citation Format

Share Document