Stereomodulating effect of remote groups on the NADH-mimetic reduction of alkyl aroylformates with 1,4-dihydronicotinamide-β-lactam amides
作者:Jesus M. Aizpurua、Claudio Palomo、Raluca M. Fratila、Pablo Ferrón、José I. Miranda
DOI:10.1016/j.tet.2010.02.085
日期:2010.4
Conformationally restricted NADH peptidomimetics 4a-e, characterized by the presence of a (1,4-dihydronicotinamide)-(beta-lactam) moiety, have been synthesized and used to study the Mg2+ cation-promoted asymmetric reduction of alkyl aroylformates in acetonitrile. Increasing the bulkiness of peripheral substituents at the nitrogen atom of the beta-lactam ring, at the 1,4-dihydronicotinamide moiety, or at the aroylformate ester group, was found to cause weak but clearly detectable variations of the enantiomeric excess of the reaction. A rational for these observations was consistent with a chelated NADH/Mg2+/ArCOCO2R3 ternary complex model, according to DFT calculations computed at a B3LYP/631G(sic) theory level. (C) 2010 Elsevier Ltd. All tights reserved.
Mechanistic Insights on the Magnesium(II) Ion-Activated Reduction of Methyl Benzoylformate with Chelated NADH Peptide β-Lactam Models
作者:Jesus M. Aizpurua、Claudio Palomo、Raluca M. Fratila、Pablo Ferrón、Ana Benito、Enrique Gómez-Bengoa、José I. Miranda、José I. Santos
DOI:10.1021/jo901236d
日期:2009.9.4
Mechanistic details of the Mg2+ ion-activated enantioselective reduction of methyl benzoylformate have been investigated at a B3LYP/6-31G* theory level, using peptide NADH models 1 rigidified with a β-lactam ring. Computation of the reaction pathway revealed important structural differences between the intermediate NADH/Mg2+/ArCOCO2R ternary complexes 3 and the corresponding transition states leading