نتایج جستجو برای: 4 michael addition

تعداد نتایج: 1922593  

1994
Jennifer Elgot-Drapkin Michael Miller Diana Gordon Madhura Nirkhe Sarit Kraus Don Perlis Donald Perlis

Even an \elementary" intelligence for control of the physical world will require very many kinds of knowledge and ability. Among these are ones related to perception, action, and reasoning about \near space": that region comprising one's body and the portion of space within reach of one's eeectors; chief among these are individuation and categorization of objects. These in turn are made useful ...

An efficient synthesis of chromenylphenylpropanone derivatives as warfarine-like analogues was developed by the Michael addition of 4-hydroxycoumarin to α,β-unsaturated compounds in the presence of polyvinylpolypyrrolidone supported antimony(III) chloride (PVPP-SbCl3) as a new polymeric Lewis acid catalyst in chloroform at reflux conditions without formation of 2,4-...

Journal: :Organic letters 2015
Xiang-Wei Du Levi M Stanley

Tandem reactions involving Rh-catalyzed intermolecular hydroacylations of alkynes with salicylaldehydes followed by intramolecular oxo-Michael additions are described for the diastereoselective synthesis of 2,3-disubstituted chroman-4-ones. The tandem hydroacylation/oxo-Michael additions occur to form 2,3-disubstituted chroman-4-ones in high yields from a range of 1,2-disubstituted acetylenes a...

Journal: :Polymer chemistry 2013
Aaron D Baldwin Kristi L Kiick

We have recently reported that retro Michael-type addition reactions can be employed for producing labile chemical linkages with tunable sensitivity to physiologically relevant reducing potentials. We reasoned that such strategies would also be useful in the design of glutathione-sensitive hydrogels for a variety of targeted delivery and tissue engineering applications. In this report, we descr...

Journal: :Chemical communications 2011
Bin Wu Guo-Gui Liu Mei-Qiu Li Yong Zhang Shao-Yun Zhang Jun-Ru Qiu Xiao-Ping Xu Shun-Jun Ji Xing-Wang Wang

Thiourea-modified cinchona alkaloids as bifunctional catalysts and a base could catalyze a stepwise [5+1] cyclization of divinyl ketones with nitromethane via double Michael additions, furnishing optically active 4-nitro-cyclohexanones with good yields, excellent diastereoselectivities (>20 : 1) and high enantiomeric ratios (up to 97 : 3).

Journal: :Organic & biomolecular chemistry 2015
Maria Moccia Robert J Wells Mauro F A Adamo

Herein, we describe a short synthesis of 3-methyl-4-nitro-5-alkylethenyl isoxazoles and their reactivity as Michael acceptors. The title compounds reacted with nitromethane under phase-transfer catalysis to provide highly enantioenriched adducts (up to 93% ee) which were then converted to the corresponding γ-nitroacids.

Journal: :Biochemical and biophysical research communications 1982
G K Powell H C Winter E E Dekker

The thioethers, S-(4-amino-2,4-dicarboxybutyl)cysteamine, S-(4-amino-2,4dicarboxybutyl)cysteine and S-(4-amino-2,4-dicarboxybuty’)glutathione, were synthesized by a Michael addition between 4-methyleneglutamic acid and the respective thiol. In dilute aqueous solution, the reactions exhibit second order kinetics; glutathione reacts much slower than cysteine or cysteamine. The adducts were charac...

Journal: :Chemical communications 2010
Takuya Hashimoto Kazuhiro Fukumoto Naoyuki Abe Kazuki Sakata Keiji Maruoka

Phase-transfer catalyzed asymmetric alkylation and Michael addition of 5-silylalkynyl-1,3-dioxolan-4-one were developed as a novel strategy to provide highly modular tertiary α-alkyl-α-hydroxy acids bearing an alkyne moiety.

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