ChemInform Abstract: Enantioselective Homogeneous Hydrogenation of Monosubstituted Pyridines and Furans

Autor:	Felix Spindler, Christina Wedemeyer-Exl, Hans-Ulrich Blaser, Martin Studer
Rok vydání:	2001
Předmět:	chemistry.chemical_classification Ligand Carboxylic acid Enantioselective synthesis chemistry.chemical_element General Medicine Medicinal chemistry Catalysis Rhodium chemistry.chemical_compound chemistry Diphosphines Chelation BINAP
Zdroj:	ChemInform. 32
ISSN:	1522-2667 0931-7597
DOI:	10.1002/chin.200116039
Popis:	The first case of an enantioselective hydrogenation of monosubstituted pyridines and furans with homogeneous rhodium diphosphine catalysts with low but significant enantioselectivities and catalyst activities is reported. Best enantioselectivities (ees of 24–27%) were obtained for the hydrogenation of 2- and 3-pyridine carboxylic acid ethyl ester and 2-furan carboxylic acid with catalysts prepared in situ from [Rh(nbd)2]BF4 and the chiral ligands diop, binap, or ferrocenyl diphosphines of the josiphos type. Turnover numbers (ton) were in the order of 10–20, turnover frequencies (tof) usually 1–2 h 1. Diphosphines giving 6- or 7-ring chelates led to higher ees than 1,2-diphosphines; otherwise, no clear correlation between ligand properties and catalytic performance was found. In some experiments black precipitates were observed at the end of the reaction, indicating the decomposition of the homogeneous catalysts for certain ligand/metal/substrate combinations.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b3b0fa491e39b15b95d4c5b41b85d7ef https://doi.org/10.1002/chin.200116039 Zobrazit plný text záznamu Plný text