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NAD(P) + ‐NADPH Models. 60. Induction of Double Asymmetry in the Reduction of α‐Keto Esters
Author(s) -
Ohno Atsuyoshi,
Yasuma Tsuneo,
Nakamura Kaoru,
Oka Shinzaburo
Publication year - 1987
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198800010
Subject(s) - chemistry , diastereomer , moiety , polarizability , stereochemistry , asymmetric induction , substrate (aquarium) , medicinal chemistry , nad+ kinase , organic chemistry , molecule , catalysis , enantioselective synthesis , enzyme , oceanography , geology
Using a chiral 1,4‐dihydronicotinamide derivative, N ‐α‐methylbenzyl‐1‐propyl‐2,4‐dimethyl‐1,4‐dihydronicotinamide (Me 2 PNPH), we have studied the reduction of various α‐keto esters that have a chiral center in the acid‐moiety. All of the four possible diastereomers of the corresponding α‐hydroxy esters were afforded. A detailed investigation into the diastereomeric composition of the product has revealed that the molecular arrangement and the conformations of the substrate at the transition state of the reduction are controlled by the polarity and/or the polarizability of the substituents. The 2 R ,3 R ‐isomer is the most predominant product when 4 R ,9 R ‐Me 2 PNPH is employed as the reductant.