Enantioselective Reduction of 3‐Aryl‐2‐oxo‐propanoic Acids: A Comparison of Enzymatic and Transition‐Metal‐Catalyzed Methods

Phenyllactic acids are important constituents of depsipeptides, which are a large class of natural products expressing a wide range of biological activities. Despite there being several methods for the enantioselective synthesis of α‐hydroxy acids, almost no studies are available addressing the substrate selectivity of transition‐metal and enzyme‐catalyzed methods for the preparation of substituted phenyllactic or more general aryllactic acids. We report herein comparative results for Rh‐DiPAMP (DiPAMP = 1,2‐ethandiylbis[( o ‐methoxyphenyl)phenylphosphane]) and lactate dehydrogenase catalyzed enantioselective reductions of several 3‐aryl‐2‐oxopropanoic acids.