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.

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

Highly Selective One-Pot Synthesis of Polysubstituted Isoflavanes using Styryl Ethers and Electron-Withdrawing ortho-Quinone Methides Generated In Situ

Synlett ◽  
2018 ◽  
Vol 30 (02) ◽  
pp. 189-192 ◽  
Author(s):  
Yujiro Hoshino ◽  
Kiyoshi Honda ◽  
Kenta Tanaka ◽  
Mami Kishimoto ◽  
Naoya Ohtsuka ◽  
...  
Keyword(s):  
Biologically Active ◽  
Quinone Methides ◽  
One Pot ◽  
One Pot Synthesis ◽  
Reaction Proceeds ◽  
Acidic Conditions ◽  
High Yields

A highly selective one-pot synthesis of polysubstituted isoflavanes has been developed. The reaction proceeds through the cycloaddition of methyl styryl ethers, derived from phenylacetaldehyde dimethyl acetals under acidic conditions, with electron-withdrawing ortho-quinone methides generated in situ. When phenylacetaldehyde dimethyl acetals were reacted with salicylaldehydes, the reaction proceeded smoothly to afford the corresponding isoflavanes stereoselectively in high yields and with excellent regioselectivities. The present reaction provides versatile access to functionalized isoflavanes, and constitutes a useful tool for the synthesis of biologically active molecules.

scholarly journals Highly Diastereoselective Synthesis of Tetrahydroquinoline Derivatives via [4 + 2] Annulation of Ortho-Tosylaminophenyl-Substituted Para-Quinone Methides and Cyanoalkenes

2021 ◽  
Vol 9 ◽  
Author(s):  
Taiwei Dong ◽  
Peifeng Wei ◽  
Min Li ◽  
Feng Gao ◽  
Yuan Qin
Keyword(s):  
Biologically Active ◽  
Structural Motif ◽  
Diastereoselective Synthesis ◽  
Atom Economy ◽  
Quinone Methides ◽  
One Pot ◽  
Reaction Performance ◽  
High Yields ◽  
Active Natural

As a privileged structural motif, tetrahydroquinoline skeletons widely exist in biologically active natural products and pharmaceuticals. In this protocol, a highly diastereoselective [4 + 2] annulation of ortho-tosylaminophenyl-substituted p-QMs and cyanoalkenes to construct tetrahydroquinoline derivatives has been successfully achieved. This strategy proceeds efficiently under mild condition, offering straightforward route to a variety of 4-aryl-substituted tetrahydroquinolines with high yields, excellent diastereoselectivities, broad functional group tolerance as well as gram-scale capacity. Moreover, a one-pot reaction sequence utilizing in situ generated p-QMs under the similar condition to build tetrahydroquinoline framework is smoothly conducted with good reaction performance as well as step and atom economy.

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.

An Organocatalytic Asymmetric Synthesis of Chiral β,β-Diaryl-α-amino Acids via Addition of Azlactones to In Situ Generated para -Quinone Methides

2018 ◽  
Vol 13 (17) ◽  
pp. 2440-2444 ◽  
Author(s):  
Jiyao Yan ◽  
Min Chen ◽  
Herman H-Y. Sung ◽  
Ian D. Williams ◽  
Jianwei Sun
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Quinone Methides

scholarly journals Application of the diastereoselective photodeconjugation of α,β-unsaturated esters to the synthesis of gymnastatin H

2011 ◽  
Vol 7 ◽  
pp. 151-155 ◽  
Author(s):  
Ludovic Raffier ◽  
Olivier Piva
Keyword(s):  
Asymmetric Synthesis ◽  
Alkoxy Group ◽  
Unsaturated Esters ◽  
Target Molecule ◽  
High Yields ◽  
Very High

The asymmetric synthesis of gymnastatin H has been achieved by using the photoisomerisation of a conjugated ester to its β,γ-unsaturated isomer through the protonation of a in situ generated dienol as key step. Thanks to diacetone D-glucose used as a chiral alkoxy group, the protonation occurred well onto one of the two diastereotopic faces with very high yields and selectivities. Moreover, by this way the configuration of the C-6 centre of the target molecule was controlled.

Indium Bromide-catalyzed Unprecedented Hydrogenolysis: A Novel One-Pot Synthesis of Per-O-Acetylated β-carboxymethyl O and S-glycosides

2020 ◽  
Vol 24 (8) ◽  
pp. 900-908
Author(s):  
Ram Naresh Yadav ◽  
Amrendra K Singh ◽  
Bimal Banik
Keyword(s):  
Asymmetric Synthesis ◽  
Chiral Auxiliary ◽  
Bioactive Molecules ◽  
One Pot ◽  
Enantiomerically Pure ◽  
Stereoselective Glycosylation ◽  
One Pot Synthesis ◽  
Wide Range

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.

Asymmetric Synthesis of Fused Tetrahydroquinolines via Intramolecular Aza-Diels-Alder Reaction of ortho-Quinone Methide Imines

Synthesis ◽  
2021 ◽  
Author(s):  
Fabian Hofmann ◽  
Cornelius Gärtner ◽  
Martin Kretzschmar ◽  
Christoph Schneider
Keyword(s):  
Asymmetric Synthesis ◽  
Alder Reaction ◽  
Single Step ◽  
Diels Alder ◽  
Quinone Methide ◽  
Bronsted Acid ◽  
Atom Economy ◽  
Diels Alder Reaction ◽  
Brönsted Acid ◽  
Chiral Bronsted Acid

Aza-Diels Alder reactions are straightforward processes in the construction of N-heterocycles, featuring inherent atom-economy and stereospecificity. Intramolecular strategies allow formation of bicyclic core structures with up to three stereocenters within a single step. Herein, this concept is combined with the chemistry of chiral Brønsted acid-bound ortho-quinone methide imines generating a range of interesting fused tetrahydro-quinolines in a diastereo- and enantioselective manner.

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