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Diasterio‐ und enantioselektive Reduktion von β‐Ketoestern mit Cyclopentanon‐, Cyclohexanon‐, Piperidon‐ und Tetralon‐Struktur durch nicht fermentierende Bäcker‐Hefe
Author(s) -
Seebach Dieter,
Roggo Silvio,
Maetzke Thomas,
Braunschweiger Hans,
Cercus Jacques,
Krieger Manfred
Publication year - 1987
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19870700618
Subject(s) - chemistry , cyclopentanone , tetralone , yeast , fermentation , substrate (aquarium) , enantioselective synthesis , enantiomer , cyclohexanone , stereochemistry , organic chemistry , medicinal chemistry , catalysis , biochemistry , oceanography , geology
Diastereo‐ and Enantioselective Reduction of beta;‐Keto Esters Derived from Cyclopentanone, Cyclohexanone, Piperidone and Tetralone by ‘Non‐fermenting’ Baker's Yeast Under ‘non‐fermenting’ conditions, i.e. in tap water, in the absence of nutrients baker's yeast (25–380 g/g of substrate, aerobic) reduces β‐keto esters such as those mentioned in the title with better selectivity than under the normally employed ‘fermenting’ conditions (sugar and nutrients, CO 2 development). With the β‐ keto esters containing the tetralone substructure, large amount of yeast are required (250–380 g/g); the substrate disappears in the biomass, and the desired reduction product can be extracted after reaction times of up to a week at 30°. The configuration of most products( 16–24 ) is established. Generally, the ( R )‐β‐keto ester is reduced faster than the ( S )‐enantiomer (the two esters are in equilibrium under the reactio conditions), and the hydride transfer takes place preferentially from the diastereotopic Re ‐face. The β‐hydroxy esters thus available are useful starting materials for syntheses of enantiomerically pure compounds (EPC).