Thioacetalization of aldehydes and ketones in the presence of hydroxo complexes of platinum(II): An example of Lewis acid catalytic activity

2001 ◽  
Vol 79 (5-6) ◽  
pp. 621-625 ◽  
Author(s):  
Lorenzo Battaglia ◽  
Francesco Pinna ◽  
Giorgio Strukul

The complex [(dppb)Pt(µ-OH)]2(BF4)2 displays high catalytic activity in the thioacetalization of a variety of aldehydes and ketones with mercaptoethanol under very mild conditions. The reaction rate is greatly enhanced by the addition to the reaction mixture of magnesium perchlorate as drying agent and molar turnovers as high as 9700 can be observed. The effect of different desiccating agents is also reported. The reactivity pattern observed, the similarity with other reactions and NMR spectroscopic investigations confirm the possible role of the complex as Lewis acid catalyst in promoting the reaction.Key words: thioacetalization, catalysis, aldehydes, ketones, platinum complex.


2020 ◽  
Author(s):  
Eric Greve ◽  
Jacob D. Porter ◽  
Chris Dockendorff

Dual amine/pi Lewis acid catalyst systems have been reported for intramolecular direct additions of aldehydes/ketones to unactivated alkynes and occasionally alkenes, but related intermolecular reactions are rare and not presently of significant synthetic utility, likely due to undesired coordination of enamine intermediates to the metal catalyst. We reasoned that bulky metal ligands and bulky amine catalysts could minimize catalyst poisoning and could facilitate certain examples of direct intermolecular additions of aldehyde/ketones to alkenes/alkynes. Density Functional Theory (DFT) calculations were performed that suggested that PyBOX-Pt(II) catalysts for alkene/alkyne activation could be combined with MacMillan’s imidazolidinone organocatalyst for aldehyde/ketone activation to facilitate desirable C-C bond formations, and certain reactions were calculated to be more exergonic than catalyst poisoning pathways. As calculated, preformed enamines generated from the MacMillan imidazolidinone did not displace ethylene from a biscationic (<i>t</i>-Bu)PyBOX-Pt<sup>2+</sup>complex, but neither were the desired C-C bond formations observed under several different conditions.



2020 ◽  
Author(s):  
Eric Greve ◽  
Jacob D. Porter ◽  
Chris Dockendorff

Dual amine/pi Lewis acid catalyst systems have been reported for intramolecular direct additions of aldehydes/ketones to unactivated alkynes and occasionally alkenes, but related intermolecular reactions are rare and not presently of significant synthetic utility, likely due to undesired coordination of enamine intermediates to the metal catalyst. We reasoned that bulky metal ligands and bulky amine catalysts could minimize catalyst poisoning and could facilitate certain examples of direct intermolecular additions of aldehyde/ketones to alkenes/alkynes. Density Functional Theory (DFT) calculations were performed that suggested that PyBOX-Pt(II) catalysts for alkene/alkyne activation could be combined with MacMillan’s imidazolidinone organocatalyst for aldehyde/ketone activation to facilitate desirable C-C bond formations, and certain reactions were calculated to be more exergonic than catalyst poisoning pathways. As calculated, preformed enamines generated from the MacMillan imidazolidinone did not displace ethylene from a biscationic (<i>t</i>-Bu)PyBOX-Pt<sup>2+</sup>complex, but neither were the desired C-C bond formations observed under several different conditions.



ChemInform ◽  
2010 ◽  
Vol 32 (52) ◽  
pp. no-no
Author(s):  
Sensuke Ogoshi ◽  
Hiromitsu Nakashima ◽  
Kazumasa Shimonaka ◽  
Hideo Kurosawa


2016 ◽  
Vol 52 (13) ◽  
pp. 2831-2834 ◽  
Author(s):  
Anindita Chakraborty ◽  
Sohini Bhattacharyya ◽  
Arpan Hazra ◽  
Ashta Chandra Ghosh ◽  
Tapas Kumar Maji

An anionic MOF shows the potential to capture toxic metal ions from water and the CuII@AMOF hybrid obtained through post-synthetic metalation is used as a Lewis acid catalyst.



Tetrahedron ◽  
2007 ◽  
Vol 63 (21) ◽  
pp. 4464-4471 ◽  
Author(s):  
Luis Ramón Domingo ◽  
Wafaa Benchouk ◽  
Sidi Mohamed Mekelleche


2021 ◽  
Author(s):  
Shuai Zhao ◽  
Juhui Zhang ◽  
Yongchang Zhai ◽  
Xiaoqin Zou ◽  
Shaolei Wang ◽  
...  

Tritylium salts have been used as Lewis acid catalyst in organic synthesis for a long time. In this work, we found that the Lewis acid catalytic activity of tritylium ions...



2021 ◽  
Author(s):  
Luis R. Domingo ◽  
Patricia Perez

The higher–order cycloaddition reactions of tropone with nucleophilic ethylenes, in the absence and presence of Lewis acid (LA) catalysts, have been studied within Molecular Electron Density Theory (MEDT) at the...



2013 ◽  
Vol 9 ◽  
pp. 1698-1704 ◽  
Author(s):  
Rajesh Munirathinam ◽  
Roberto Ricciardi ◽  
Richard J M Egberink ◽  
Jurriaan Huskens ◽  
Michael Holtkamp ◽  
...  

Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS). XPS revealed the presence of one gallium per 2–3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-functionalized brushes in a microreactor was demonstrated for the dehydration of oximes, using cinnamaldehyde oxime as a model substrate, and for the formation of oxazoles by ring closure of ortho-hydroxy oximes. The catalytic activity of the microreactor could be maintained by periodic reactivation by treatment with GaCl3.



CrystEngComm ◽  
2015 ◽  
Vol 17 (37) ◽  
pp. 7124-7129 ◽  
Author(s):  
Zhigang Hu ◽  
Yongwu Peng ◽  
Kai Min Tan ◽  
Dan Zhao

A hierarchical porous metal–organic framework CuBTC with mesopores of 3.9 nm pore size has been facilely obtained as Lewis acid catalyst.



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