scholarly journals Half‐sandwich nickel(II) NHC‐picolyl complexes as catalysts for the hydrosilylation of carbonyl compounds: evidence for NHC‐nickel nanoparticles under harsh reaction conditions

Author(s):  
Franck Ulm ◽  
Saurabh Shahane ◽  
Lai Truong-Phuoc ◽  
Thierry Romero ◽  
Vasiliki Papaefthimiou ◽  
...  
2016 ◽  
Vol 2016 (21) ◽  
pp. 3469-3473 ◽  
Author(s):  
Daeho Kim ◽  
Hyuntae Kang ◽  
Hyesu Park ◽  
Sungkyun Park ◽  
Ji Chan Park ◽  
...  

2007 ◽  
Vol 2007 (8) ◽  
pp. 486-489 ◽  
Author(s):  
Mahmood Tajbakhsh ◽  
Setareh Habibzadeh

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.


2021 ◽  
Author(s):  
Anurag Kumar ◽  
Yifat Harel ◽  
Jean-paul Lellouche ◽  
Suman L. Jain

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.


Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1338
Author(s):  
Marek Gliński ◽  
Ewa M. Iwanek (nee Wilczkowska) ◽  
Urszula Ulkowska ◽  
Agnieszka Czajka ◽  
Zbigniew Kaszkur

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.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Mantu Rajbangshi ◽  
Md. Rumum Rohman ◽  
Icydora Kharkongor ◽  
Hormi Mecadon ◽  
Bekington Myrboh

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.


2008 ◽  
Vol 49 (12) ◽  
pp. 1939-1942 ◽  
Author(s):  
Francisco Alonso ◽  
Paola Riente ◽  
Miguel Yus

2005 ◽  
Vol 2005 (2) ◽  
pp. 88-90 ◽  
Author(s):  
Weike Su ◽  
Jin Can

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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