Reaction of Lithiated Propargyl Ethers with Carbonyl Compounds – A Regioselective Route to Furan Derivatives

Synthesis ◽  
2020 ◽  
Author(s):  
Hans-Ulrich Reissig ◽  
Igor Linder ◽  
Robby Klemme
Keyword(s):  
Diethyl Ether ◽  
Carbonyl Compounds ◽  
Reaction Conditions ◽  
Furan Derivatives ◽  
Proton Shift ◽  
Propargyl Ether ◽  
Ambident Anion

AbstractThe deprotonation of 3-aryl-substituted alkyl propargyl ethers with n-butyllithium provides an ambident anion that reacts with carbonyl compounds to provide mixtures of γ-substituted products with alkoxyallene substructure and of α-substituted propargyl ethers. The ratio of the two product types strongly depends on the solvent: in diethyl ether the γ-substituted products predominate whereas the more polar tetrahydrofuran favors the α-adducts. The primary addition products undergo 5-endo-trig or 5-endo-dig cyclizations under various reaction conditions to afford isomeric furan derivatives. The highest selectivity in favor of α-substituted products was achieved by employing a MOM-protected propargyl ether. During the protonation step no evidence for a proton shift leading to an isomeric allenyl anion was found. A brief mechanistic discussion tries to rationalize the observed regio­selectivities.

Cleavage of C=N derivatives and Oxidation of Thiols in Water under Neutral Conditions with 1,4-dichloro-1,4-diazoniabicyclo[2,2,2]octane bischloride

2007 ◽  
Vol 2007 (8) ◽  
pp. 486-489 ◽  
Author(s):  
Mahmood Tajbakhsh ◽  
Setareh Habibzadeh
Keyword(s):  
Carbonyl Compounds ◽  
High Yield ◽  
Reaction Conditions ◽  
Neutral Conditions

1,4-Diazabicyclo[2,2,2]octane (DABCO) is easily chlorinated and gives a complex which efficiently converts aliphatic and aromatic oximes, phenylhydrazones and semicarbazones to their corresponding carbonyl compounds in water at 50°C in high yield. This reagent can also be used for conversion of thiols to their compounding disulfide under the same reaction conditions. DABCO is quantitatively recovered which can be rechlorinated and reused several times.

Novel Ceric Ammonium Nitrate-Stabilized Maghemite Nanoparticles (CAN-γ-Fe2O3) for Ultrasound Assisted Synthesis of β-Amino Derivatives

2021 ◽  
Author(s):  
Anurag Kumar ◽  
Yifat Harel ◽  
Jean-paul Lellouche ◽  
Suman L. Jain
Keyword(s):  
Carbonyl Compounds ◽  
Addition Reaction ◽  
Ceric Ammonium Nitrate ◽  
Reusable Catalyst ◽  
Maghemite Nanoparticles ◽  
Reaction Conditions ◽  
Recyclable Catalysts ◽  
Nucleophilic Addition Reaction ◽  
Amino Derivatives ◽  
Positively Charged

Abstract Owing to their inherent features like smaller size and higher surface area exposed to reactants, nanoparticles have gained enormous interest and are extensively used as magnetically recyclable catalysts for various organic reactions. Herein, we report highly hydrophilic, non-aggregated, and strongly positively charged (ζ potential: +45.7 mV) ultra-small cerium cations/complexes- stabilized maghemite nanoparticles in water as an efficient and reusable nanoscaled magnetically active catalyst for the nucleophilic addition reaction of various amines with α,β-unsaturated carbonyl compounds to give corresponding β-amino derivatives under ultrasonic irradiation. The developed protocol provides several merits such as high product yields, mild reaction conditions, reusable catalyst and easy workup.

scholarly journals Catalytic Activity of High-Surface-Area Amorphous MgO Obtained from Upsalite

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1338
Author(s):  
Marek Gliński ◽  
Ewa M. Iwanek (nee Wilczkowska) ◽  
Urszula Ulkowska ◽  
Agnieszka Czajka ◽  
Zbigniew Kaszkur
Keyword(s):  
Surface Area ◽  
Carbonyl Compounds ◽  
Main Product ◽  
High Surface ◽  
High Surface Area ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Reaction Conditions ◽  
Synthesis Conditions ◽  
Transfer Hydrogenation Reaction

The first aim of the research was to synthesize a pure Upsalite, which is an amorphous form of MgCO3, by modifying a procedure described in the literature, so that it would be the precursor of a high-surface, amorphous magnesium oxide. The results indicate that within the studied reaction conditions, the type of alcohol used as the reactant has the most pronounced effect on the yield of reaction. From the two alcohols that led to the highest yield of Upsalite, methanol gave a substantially larger surface area (794 vs. 191 m2 g−1). The optimized synthesis conditions of Upsalite were used to obtain MgO via thermolysis, whose activity in the transfer hydrogenation reaction (THR) from ethanol, 2-propanol and 2-pentanol to various carbonyl compounds was determined. The optimal conditions for the thermolysis were as follows: vacuum, T = 673 K as the final temperature, and a heating rate of 2 deg min−1. The high-surface, amorphous magnesia (SBET = 488 m2 g−1) was found to be a very selective catalyst to 4-t-butylcyclohexanone in THR, which led to a diastereoselectivity of over 94% to the E-isomer of 4-t-butylcyclohexanol for more than 3 h, with conversions of up to 97% with either 2-propanol or 2-pentanol as the hydrogen donor. In the case of acrolein and 2-n-propylacrolein being used as the hydrogen acceptors, the unsaturated alcohol (UOL) was the main product of the reaction, with higher UOL yields noted for ethanol than 2-propanol.

ChemInform Abstract: Chemo- and Regioselective Conversion of Epoxides to Carbonyl Compounds in 5 M Lithium Perchlorate-Diethyl Ether Medium.

ChemInform ◽  
2010 ◽  
Vol 27 (30) ◽  
pp. no-no
Author(s):  
R. SUDHA ◽  
K. M. NARASIMHAN ◽  
V. G. SARASWATHY ◽  
S. SANKARARAMAN
Keyword(s):  
Diethyl Ether ◽  
Carbonyl Compounds ◽  
Lithium Perchlorate

scholarly journals Synthesis of β-Amino Carbonyl Compounds via the Iodine-Alumina Catalyzed Three-Component Coupling Reaction under Microwave Irradiation

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Mantu Rajbangshi ◽  
Md. Rumum Rohman ◽  
Icydora Kharkongor ◽  
Hormi Mecadon ◽  
Bekington Myrboh
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Carbonyl Compounds ◽  
Aromatic Amines ◽  
Coupling Reaction ◽  
Environmentally Friendly ◽  
Coupling Reactions ◽  
Reaction Conditions ◽  
Key Features ◽  
Operational Simplicity

Iodine-alumina was employed as a catalyst in the coupling reactions of aldehydes, enolizable ketones, or 1,3-dicarbonyls with methyl carbamate or aromatic amines under microwave irradiation to afford β-amino carbonyl compounds in good-to-excellent yields. The key features of this environmentally friendly methodology are its operational simplicity, mild reaction conditions, and less reaction time.

Zn(OTf)2.6H2O catalysed acylation of aldehydes: Preparation of 1,1-diacetates and α-chloroalkyl esters

2005 ◽  
Vol 2005 (2) ◽  
pp. 88-90 ◽  
Author(s):  
Weike Su ◽  
Jin Can
Keyword(s):  
Carbonyl Compounds ◽  
Reaction Conditions ◽  
Zinc Triflate

1,1-Diacetates (acylals) and α-chloroalkyl esters were prepared from carbonyl compounds with acylating reagents in the presence of 5% mol hexaaqua zinc triflate [Zn(OTf)2.6H2O] with good yields under mild reaction conditions.

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