29365-71-7Relevant academic research and scientific papers
Ruthenium(II)-Chitosan, an Enantioselective Catalyst for the Transfer Hydrogenation of N-Heterocyclic Ketones
Kolcsár, Vanessza Judit,Fül?p, Ferenc,Sz?ll?si, Gy?rgy
, p. 2725 - 2731 (2019/05/24)
The present study aimed at extending the applicability of a recently developed stereoselective catalytic system to the preparation of optically enriched N-heterocyclic alcohols. Chiral ruthenium catalyst formed in situ using the chitosan biopolymer as ligand, which provided good results in the transfer hydrogenation of heterobicyclic compounds, such as 4-chromanone and 4-thiochromanone, was used in reactions of various N-containing prochiral ketones. High enantioselectivities were reached in transfer hydrogenations of bicyclic compounds bearing nitrogen either in aromatic or cycloaliphatic moieties, provided that the amino group was protected or shielded by a nearby substituent. Results were rationalized by interactions of the nitrogen with the metal and/or ligand. N-containing bicyclic compounds having heteroatoms in both rings were also prepared and tested. The detrimental effect of the pyridyl moiety was compensated by the beneficial influence of the heteroatom in the cycloaliphatic ring, as indicated by high rates and good enantioselectivities obtained in reactions of these compounds. Preparation of several N-heterocyclic alcohols, in good yields and high optical purities was achieved using Ru(II)-chitosan complex.
NOVEL RUTHENIUM CATALYSTS AND THEIR USE FOR ASYMMETRIC REDUCTION OF KETONES
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Page/Page column 21, (2015/01/16)
Disclosed are novel ruthenium compounds of formula (Ia) and (Ib): wherein R1 and the moiety L ∩ L are defined herein. Also disclosed is a process for using these novel ruthenium compounds as catalysts for asymmetric hydrogenation and transfer hydrogenation of ketones with high reactivities and excellent selectivities.
Amine-tunable ruthenium catalysts for asymmetric reduction of ketones
Rodriguez, Sonia,Qu, Bo,Fandrick, Keith R.,Buono, Frederic,Haddad, Nizar,Xu, Yibo,Herbage, Melissa A.,Zeng, Xingzhong,Ma, Shengli,Grinberg, Nelu,Lee, Heewon,Han, Zhengxu S.,Yee, Nathan K.,Senanayake, Chris H.
, p. 301 - 307 (2014/05/20)
A series of efficient ruthenium catalysts has been developed for the asymmetric hydrogenation and transfer hydrogenation of ketones with high reactivities and selectivities. The new chiral bisdihydrobenzooxaphosphole (BIBOP)/diamineruthenium complexes catalyzed the enantioselective hydrogenation of substrates such as aryl and heteroaryl cyclic and alkyl ketones with substrate/catalyst (S/C) ratios of up to 100,000. The opposite sense of enantioselectivity can be obtained by proper selection of a diamine with a given chirality of the phosphine. The usefulness of the new system has been demonstrated in the asymmetric hydrogenation of a complex synthetic intermediate towards cholesteryl ester transfer protein (CETP) inhibitors at S/C 20,000 on large-scale operation.
