Peter Pöchlauer

Enzyme catalysed formation of (S)-cyanohydrins derived from aldehydes and ketones in a biphasic solvent system

Abstract By employing a vigorously stirred two phase system aqueous buffer/organic solvent and using the hydroxynitrile lyase from Hevea brasiliensis as biocatalyst enantiopure ( S )-cyanohydrins from aliphatic, unsaturated, aromatic and heteroaromatic aldehydes and methyl alkyl and methyl phenyl ketones are obtained in high yield and in general 98–99% enantiomeric excess.

ONE-POT FORMATION OF SUCCINIMIDYL ESTERS BY THE SYSTEM CHLOROPHOSPHATE/HYDROXYSUCCINIMIDE/BASE

Abstract Succinimidyl esters of various carboxylic acids are formed in high yield at ambient to slightly elevated temperature by the system chlorophosphate / hydroxysuccinimide / base.

(αMe)Hyv: chemo-enzymatic synthesis, and preparation and preferred conformation of model depsipeptides

By a chemo-enzymatic approach we performed a large-scale, stereoselective synthesis of the Cα-methylated α-hydroxy acid L-(αMe)Hyv. We also prepared model depsipeptides based on this sterically demanding residue in combination with the α-amino acids L-Ala, L-Val, and Aib. From solution (FT-IR absorption and 1H NMR) and crystal-state (X-ray diffraction) conformational analyses we found that L-(αMe)Hyv forces depsipeptides to fold into right-handed β-turn/helical structures by analogy with the reported propensity of L-(αMe)Val, its α-amino acid counterpart.