Chemistry Reference
In-Depth Information
6
ENZYME - CATALYZED ASYMMETRIC
SYNTHESIS
HARALD GR Ö GER
Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg,
Erlangen, Germany
6.1. INTRODUCTION
Biocatalysis has been recognized over the past decades as a highly valuable tool for
organic chemists to prepare enantiomerically pure molecules, so-called chiral building
blocks, in a highly effi cient way. Besides a multitude of academic work, it is noteworthy
that enzyme catalysis belongs to the standard repertoire in industry when facing chal-
lenging enantioselective synthetic routes. A broad range of biocatalytic methods is
already in use in particular for large-scale manufacture of drug intermediates [1].
The research in the fi eld of enzyme catalysis has already been comprehensively
reviewed some years ago [2]. Thus, the focus of the current review is on a selection of
(particularly recently developed) enantioselective enzymatic reactions, which turned out
to be highly useful and applicable in organic synthesis, fulfi lling criteria such as high
productivity, substrate concentrations, conversions, and enantioselectivities. The pre-
sented methods are an interesting complementary tool to existing “classic organic” or
“chemocatalytic asymmetric” methodologies. Among biocatalytic reactions, both reso-
lution of racemates and asymmetric synthesis starting from prochiral substrates are
attractive routes already applied, in part, in industry. A third type of biotechnological
approach, which is not a subject of this review, are fermentation processes. A graphical
summary of these three types of so-called “white biotechnology” methodologies is given
in Scheme 6.1 .
Hydrolases are the enzyme class most commonly applied as biocatalysts in organic
chemistry. This is mainly due to the accessibility of these enzymes (used, e.g., in the
textile and detergents industry), their suitability for transformations in organic media
