Premium
Theoretical investigation of the enantioselective hydrogenation of α‐ketoesters over pt/alumina modified with cinchonidine
Author(s) -
Schwalm O.,
Weber J.,
Minder B.,
Baiker A.
Publication year - 1994
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560520119
Subject(s) - quinuclidine , enantioselective synthesis , cinchonidine , chemistry , asymmetric hydrogenation , catalysis , computational chemistry , cinchona , hydrogen bond , substrate (aquarium) , cinchona alkaloids , moiety , transition metal , van der waals force , organic chemistry , molecule , oceanography , geology
Enantioselective hydrogenation of α‐ketoesters with cinchona‐modified platinum catalysts has been studied theoretically in order to rationalize the interaction between the chiral modifier and the substrate. The structure of the probable transition complex has been calculated for the system methyl pyruvate (substrate)–cinchonidine (modifier) using quantum chemistry techniques at both ab initio and semiempirical levels and molecular mechanics. The calculations indicate that crucial interaction occurs via hydrogen bonding of the quinuclidine nitrogen and the oxygen of the α‐carbonyl moiety of methyl pyruvate and confirm earlier experimental evidence that the quinuclidine nitrogen of the cinchonidine is involved in the interaction leading to enantiodifferentiation. The resulting complex, which resembles to a half‐hydrogenated state of the substrate, is shown to be a possible transition state for the enantioselective hydrogenation of α‐ketoesters. © 1994 John Wiley & Sons, Inc.