نتایج جستجو برای: Intramolecular Michael-addition

تعداد نتایج: 747019  

Journal: :journal of physical & theoretical chemistry 2005
hojatollah salehi mohammad rabbani qian-rong li qing-xiang guo

an efficient and environmentally friendly procedure for one-pot synthesis of 13-acetyl-9-methyl-11-ox-8-oxa-10,12-diazatricyclo [7.3.1. ] trideca-2,4,6-triene from salicylaldehyde, acetylaceton and urea via biginelli condensation and intramolecular michael-addition by using magnesium bromide as an expensive and easily available catalyst under solvent-free condition is desired. the structural el...

Hojatollah Salehi Mohammad Rabbani Qian-Rong Li Qing-xiang Guo

An efficient and environmentally friendly procedure for one-pot synthesis of 13-acetyl-9-methyl-11-ox-8-oxa-10,12-diazatricyclo [7.3.1. ] trideca-2,4,6-triene from salicylaldehyde, acetylaceton and urea via Biginelli condensation and intramolecular Michael-addition by using magnesium bromide as an expensive and easily available catalyst under solvent-free condition is desired. The structural el...

Journal: :Journal of the American Chemical Society 2005
Roy Weinstain Richard A Lerner Carlos F Barbas Doron Shabat

The development of new catalytic asymmetric reactions continues to be a major goal in organic chemistry. Here we report a novel antibody-catalyzed intramolecular Michael addition of aldehydes and ketones to enones. The reaction is enantioselective and diastereoselective with a high ee value and cis/trans ratio. This is the first example of asymmetric intramolecular Michael addition of ketones. ...

An efficient cyclization of 2’-hydroxychalcone to flavanone using calcium chloride as a catalyst was developed. The scope of the reaction was studied with substituted 2’-hydroxychalcone and these chalcones was converted into corresponding flavanone in good yield. The merits of this method are inexpensive and easily available catalyst, easy workup procedure, avoid use of toxic solvent

An efficient cyclization of 2’-hydroxychalcone to flavanone using calcium chloride as a catalyst was developed. The scope of the reaction was studied with substituted 2’-hydroxychalcone and these chalcones was converted into corresponding flavanone in good yield. The merits of this method are inexpensive and easily available catalyst, easy workup procedure, avoid use of toxic solvent. 

Journal: :Organic & biomolecular chemistry 2010
Hu He Li-Xin Dai Shu-Li You

A convenient synthesis of benzyl-gamma-butyrolactone derivatives via intramolecular Michael addition reaction of nitro-substituted aryl allyl beta-ketocarboxylates is reported. The method features simple operation, mild reaction conditions and high efficiency.

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: :Journal of the American Chemical Society 2005
Javier Read de Alaniz Tomislav Rovis

A highly enantio- and diastereoselective intramolecular Stetter reaction has been developed. Subjection of alpha,alpha-disubstituted Michael acceptors to an asymmetric intramolecular Stetter reaction results in a highly enantioselective conjugate addition and a diastereoselective proton transfer. Available evidence suggests the diastereoselective protonation occurs via intramolecular delivery t...

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