نتایج جستجو برای: michael addition

تعداد نتایج: 735143  

Journal: :Molecules 2012
Luis R Domingo Ramón J Zaragozá Jose A Saéz Manuel Arnó

The mechanism of the N-heterocyclic carbene (NHC)-catalyzed intramolecular Stetter reaction of salicylaldehyde 1 to yield chromanone 3 has been theoretically studied at the B3LYP/6-31G** level. This NHC-catalyzed reaction takes place through six elementary steps, which involve: (i) formation of the Breslow intermediate IN2; (ii) an intramolecular Michael-Type addition in IN2 to form the new C-C...

Journal: :Chemical science 2015
Alejandro Cabanillas Christopher D Davies Louise Male Nigel S Simpkins

Michael addition reactions of triketopiperazine (TKP) derivatives to enones, mediated by a cinchona alkaloid-derived catalyst, deliver products in high yield and enantiomeric ratio (er). Use of unsaturated ester, nitrile or sulfone partners gives bridged hydroxy-diketopiperazine (DKP) products resulting from a novel Michael addition-ring closure.

Journal: :Chemical communications 2014
Emilia Oueis Florian Nachon Cyrille Sabot Pierre-Yves Renard

The irreversible Michael addition of thiols to acrylamides is reported as a new tool for the kinetic target-guided synthesis. In an unprecedented enzymatic hydrolysis/thio-Michael addition procedure, potent and selective acetylcholinesterase inhibitors are assembled by the enzyme using both its esterasic and templating ability.

2014
Pankaj Chauhan Gregor Urbanietz Gerhard Raabe Dieter Enders

A highly stereoselective one-pot procedure involving an enantioselective Michael addition promoted by low loading of an amino-squaramide catalyst followed by an achiral base catalyzed domino Michael-Knoevenagel-type 1,2-addition sequence provides efficient access to fully substituted cyclohexanes bearing five contiguous stereogenic centers in good yields (68-86%) and excellent stereoselectiviti...

Journal: :Chemical communications 2015
Abdelbari Ben Abdessalem Raoudha Abderrahim Asma Agrebie Aurélie Dos Santos Laurent El Kaïm Andrii Khomenko

Ugi adducts derived from aromatic aldehydes may be converted to pyrrolines via addition of Michael acceptors under microwave irradiation. The reaction may proceed via unusual formation of azomethine ylides followed by a [3+2] cycloaddition using Michael acceptors.

Journal: :Organic & biomolecular chemistry 2014
Ahmed Kamal Manda Sathish Vunnam Srinivasulu Jadala Chetna Kunta Chandra Shekar Shalini Nekkanti Yellaiah Tangella Nagula Shankaraiah

Chiral pyrrolidinyl-oxazole-carboxamides were synthesized and used as efficient new organocatalysts for the asymmetric Michael addition of ketones with nitroalkenes under solvent-free conditions. Gratifyingly, the corresponding Michael adducts were obtained in higher yields (up to 99%) and excellent stereoselectivities (up to >99/1 dr and 99% ee). Transition state models have been proposed to a...

Journal: :زبان و زبان شناسی 0
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