Modifier–substrate interactions of various types in the Orito reaction: Reversal of the enantioselection in the hydrogenation of ketopantolactone on Pt modified by β-isocinchonine and O-phenylcinchonidine

Autor:	Mihály Bartók, Tibor Bartók, György Szőllősi, Katalin Balázsik, Imre Bucsi
Rok vydání:	2013
Předmět:	Process Chemistry and Technology Enantioselective synthesis Substrate (chemistry) chemistry.chemical_element General Chemistry Toluene Medicinal chemistry Catalysis Adduct Acetic acid chemistry.chemical_compound chemistry Ketopantolactone Organic chemistry Platinum
Zdroj:	Catalysis Communications. 32:81-85
ISSN:	1566-7367
DOI:	10.1016/j.catcom.2012.12.009
Popis:	The enantioselective hydrogenation of ketopantolactone (KPL) on Pt–alumina catalyst modified by β-isocinchonine (β-ICN) and O -phenylcinchonidine (PhOCD) in toluene, acetic acid and their mixtures under otherwise identical experimental conditions was studied. Reversal of the enantioselection was obtained dependent on the concentration of acetic acid (ee max = 17% ( S ) on Pt–PhOCD and 50% ( R ) on Pt–β-ICN, respectively). The possible role in enantioselection of adducts forming in the reaction mixture and the stability of PhOCD under the conditions of the hydrogenation was investigated by ESI-MS. The results of the nonlinear phenomenon measurements on β-ICN + PhOCD mixtures suggest that the intermediate surface complexes β-ICN–KPL and PhOCD–KPL responsible for the opposite enantioselection include different types of interactions and the enantioselection is directed by the competition between these interactions.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::2ca1964481a61cae43625e99fdb5d911 https://doi.org/10.1016/j.catcom.2012.12.009 Zobrazit plný text záznamu Full Text from ScienceDirect