Enantioselective hydrogenation of α-ketoesters using cinchona modified platinum catalysts and related systems: A review

MCM-41-supported platinum carbonyl cluster-derived catalysts for asymmetric and nonasymmetric hydrogenation reactions

“…Benzonitrile and ethylacetoacetate were purchased from Spectrochem Pvt. Ltd. Nitrobenzene and aniline were obtained from Merck Ltd. MCM-41 and Na 2 [Pt 12 (CO) 24 ] were synthesized as described previously [57,58]. All of the hydrogenation reactions were carried out in an autoclave.…”

“…Anionic platinum carbonyl cluster ([Pt 12 (CO) 24 ] 2− ) was ion-paired with the 3-chloropropyltrimethoxysilyl-ammonium group chemically bound to the surface of MCM-41. The materials undergo quick decarbonylation and have been characterized before decarbonylation by IR and UV-vis spectroscopy and after decarbonylation by XPS and TEM.…”

“…Here a conventional heterogeneous catalyst, such as platinum or raney nickel, is modified by treatment with readily available chiral substances . Although the overall success of this approach has been limited, platinum on alumina modified by cinchona alkaloids has been found to be a particularly effective catalyst for the enantioselective hydrogenation of α-ketoesters in general and pyruvate esters in particular [21][22][23][24][25][26][27][28][29][30][31][32][33]. This reaction is commonly referred to as the Orito reaction, in honor of its discoverer.…”

“…We reported hydrogenation of ketones where the Chini cluster [Pt 12 (CO) 24 ] 2− ion paired on functionalized fumed silica was used as the precatalyst [32]. The catalyst was found to be more active than the material obtained by physical adsorption of [Pt 12 (CO) 24 ] 2− on the support.…”

Catalytic hydrogen transfer over magnesia. Part XXV. Liquid and vapor phase reduction of ketoesters

“…The presence of the prochiral carbonyl group in their molecules focuses attention of many chemists due to the stereochemical aspects of its asymmetric hydrogenation in the presence of metallic catalysts modified by various chiral auxiliaries [29,30]. Although the CTH of various carbonyl compounds has been studied systematically since the 1970s, the reduction of ketoesters by this method has remained unexplored until almost the present day.…”