Phenyllactic acids are found in numerous natural products as well as in active substances used in medicine or plant protection. Enantiomerically pure phenyllactic acids are available by transition-metal-catalyzed hydrogenations or chemoenzymatic reductions of the corresponding 3-aryl-2-oxopropanoic acids. We show here that d-lactate dehydrogenase from Staphylococcus epidermidis reduces a broad spectrum of 2-oxo acids, which are difficult substrates for transition-metal-catalyzed reactions, with excellent enantioselectivities in a simple experimental setup.

The first neutral gold­(III) triazido compounds stabilized by N-heterocyclic carbenes were prepared and structurally characterized. Various 1,3-dipolar cycloaddition reactions were examined with these compounds. Isothiocyanates and t BuNC gave the expected cycloaddition products; however, these were accompanied by reduction to gold­(I). Examination of the photophysical properties of the triazido compounds in solution revealed that photoreduction to gold­(I) species occurs readily.

A series of ethynyl gold(I) complexes with N-heterocyclic carbene ligands were prepared through a transmetallation procedure using either nBu 3 SnC≡CH or TMSC≡CH in the presence of fluoride ions. This methodology represents the first [a]

Enantiomerically Pure 3-Aryl-and 3-Hetaryl-2-hydroxypropanoic Acids by Chemoenzymatic Reduction of 2-Oxo Acids. -A coupled enzyme system in one pot allows the preparation of the title compounds in enantiomerically pure form. The target compounds are prepared either from the methyl esters via their lithium salts or directly from the oxo acids. -(SIVANATHAN, S.; KOERBER, F.; TENT, J. A.; WERNER, S.; SCHERKENBECK*, J.; J. Org. Chem. 80 (2015) 5, 2554-2561, http://dx.