Microbial reduction of 1-tetralone 2-carboxyesters as a source of new asymmetric synthons
摘要:
The reduction of unsubstituted or methoxy-substituted (+/-)-2-carboxyethyl-1-tetralones by selected microorganisms affords optically active 1-hydroxy-2-carboxyethyl tetralins which can be used as versatile asymmetric synthons, for example in the preparation of biologically active methoxy-substituted 2R-aminotetralins. 1R,2R-(cis)-hydroxyesters of high optical purity are obtained with yeast strains, while the use of filamentous fungi leads to the enantiomeric 1S,2S-(cis)-hydroxyesters.
Microbial reduction of 1-tetralone 2-carboxyesters as a source of new asymmetric synthons
摘要:
The reduction of unsubstituted or methoxy-substituted (+/-)-2-carboxyethyl-1-tetralones by selected microorganisms affords optically active 1-hydroxy-2-carboxyethyl tetralins which can be used as versatile asymmetric synthons, for example in the preparation of biologically active methoxy-substituted 2R-aminotetralins. 1R,2R-(cis)-hydroxyesters of high optical purity are obtained with yeast strains, while the use of filamentous fungi leads to the enantiomeric 1S,2S-(cis)-hydroxyesters.
The reduction of racemic beta-keto esters having the tetralone structure by chiral ruthenium(II) catalysts is realized with an ideal kinetic dynamic resolution. Remarkably, high anti selectivity approaching 100% and enantioselectivity (up to 97%) using atropisomeric ligands are obtained. The trans beta-hydroxy esters thus available are useful starting materials for production of enantiomerically pure compounds.