ChemInform Abstract: Combining NHC-Cu and Broensted Base Catalysis: Enantioselective Allylic Substitution/Conjugate Additions with Alkynylaluminum Reagents and Stereospecific Isomerization of the Products to Trisubstituted Allenes.

ChemInform ◽  
2013 ◽  
Vol 44 (49) ◽  
pp. no-no
Author(s):  
Jennifer A. Dabrowski ◽  
Frederik Haeffner ◽  
Amir H. Hoveyda
Keyword(s):  
Base Catalysis ◽  
Allylic Substitution ◽  
Conjugate Additions

scholarly journals Facile and efficient conjugate additions of β-dicarbonyl compounds and nitroalkanes to 4-aryl-4-oxobut-2-enoates

2011 ◽  
Vol 76 (7) ◽  
pp. 947-954 ◽  
Author(s):  
Xin Lv ◽  
Yaohong Zhang ◽  
Liejin Zhou ◽  
Xiaoxia Wang
Keyword(s):  
Base Catalysis ◽  
Conjugate Additions ◽  
Dicarbonyl Compounds ◽  
Carbon Nucleophiles ◽  
Keto Esters

Facile and efficient conjugate additions of carbon nucleophiles, such as ?-dicarbonyl compounds and nitroalkanes, to 4-aryl-4-oxobut-2-enoates have been achieved under simple base catalysis. A variety of multi-functional ?-keto esters could be conveniently obtained in good to excellent yields with complete regioselectivity.

Conjugate Additions of Organolithiums to Electron-poor Olefins: A Simple and Useful Approach to the Synthesis of Complex Molecules

2016 ◽  
Vol 21 (3) ◽  
pp. 190-217 ◽  
Author(s):  
Paola Vitale ◽  
Vito Capriati ◽  
Saverio Florio ◽  
Filippo Perna ◽  
Antonio Salomone
Keyword(s):  
Conjugate Additions ◽  
Complex Molecules

Palladium-Catalyzed Asymmetric Allylic Substitution Using Phosphoramidite Ligands Bearing 1,1-Binaphthyl Skeleton

2008 ◽  
Vol 5 (5) ◽  
pp. 346-348 ◽  
Author(s):  
Yongguang Gao ◽  
Xinsheng Li ◽  
Weiyi Chen ◽  
Dongcheng Xu
Keyword(s):  
Allylic Substitution ◽  
Palladium Catalyzed

Kinetics of cyclization of S-ethoxycarbonylmethylisothiouronium chloride to 2-imino-4-thiazolidone

1979 ◽  
Vol 44 (3) ◽  
pp. 912-917 ◽  
Author(s):  
Vladimír Macháček ◽  
Said A. El-bahai ◽  
Vojeslav Štěrba
Keyword(s):  
Hydrochloric Acid ◽  
Dilute Hydrochloric Acid ◽  
Base Catalysis ◽  
General Base ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Rate Limiting ◽  
Kinetics Of

Kinetics of formation of 2-imino-4-thiazolidone from S-ethoxycarbonylmethylisothiouronium chloride has been studied in aqueous buffers and dilute hydrochloric acid. The reaction is subject to general base catalysis, the β value being 0.65. Its rate limiting step consists in acid-catalyzed splitting off of ethoxide ion from dipolar tetrahedral intermediate. At pH < 2 formation of this intermediate becomes rate-limiting; rate constant of its formation is 2 . 104 s-1.

Mechanism of hydration and isomerisation of 4-ethylidene-2,6-di-tert-butyl-2,5-cyclohexadien-1-one. Kinetics, acid-base catalysis and solvent deuterium isotope effects

1979 ◽  
Vol 44 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Jiří Velek ◽  
Bohumír Koutek ◽  
Milan Souček
Keyword(s):  
Aqueous Medium ◽  
Rate Equation ◽  
Kinetic Data ◽  
Isotope Effects ◽  
Base Catalysis ◽  
Quinone Methide ◽  
Reaction Products ◽  
Acid Base ◽  
Deuterium Isotope Effects ◽  
Hydroxybenzyl Alcohol

Competitive hydration and isomerisation of the quinone methide I at 25 °C in an aqueous medium in the region of pH 2.4-13.0 was studied spectrophotometrically. The only reaction products in the studied range of pH are 4-hydroxybenzyl alcohol (II) and 4-hydroxystyrene (III). The form of the overall rate equation corresponds to a general acid-base catalysis. The mechanism of both reactions for three markedly separated pH regions is discussed on the basis of kinetic data and solvent deuterium effect.

Pulse polarographic study of the behaviour of some o,o'-dihydroxyazo-compounds

1989 ◽  
Vol 54 (5) ◽  
pp. 1219-1226 ◽  
Author(s):  
Enric Casassas ◽  
Miquel Esteban ◽  
Santiago Alier
Keyword(s):  
Carboxylic Acid ◽  
Reaction Mechanisms ◽  
Sulphonic Acid ◽  
Base Catalysis ◽  
Polarographic Study ◽  
Acid Base ◽  
Eriochrome Black T ◽  
Naphthoic Acid ◽  
Calcon Carboxylic Acid

The reduction of several o,o'-dihydroxyazo-compounds is studied by means of pulse polarographic techniques (DPP, NPP and RPP). The compounds studied are the following: 2-(2'-hydroxyphenylazo)-phenol (o,o'-dihydroxyazobenzene), 1-(2'-hydroxy-1'-naphthylazo)-2-naphthol-4-sulphonic acid (calcon or Eriochrome Blue Black R), 1-(2'-hydroxy-4'-sulpho-1'-naphthylazo)-2-hydroxy-3-naphthoic acid (calcon carboxylic acid), and 1-(1'-hydroxy-2'-naphthylazo)-6-nitro-2-naphthol-4-sulphonic acid (Eriochrome Black T). Correlations between Ip and Epand experimental variables (pH, T, conc.) and instrumental parameters (dropping time, t, and pulse magnitude, ΔE) are established. Reaction mechanisms formerly proposed are discussed on the basis of the new obtained results, and the ranges are defined where adsorption and/or acid-base catalysis are operative.

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