Applying Biocatalysis to the Synthesis of Diastereomerically Enriched Cyanohydrin Mannosides

Abstract

Abstract Fully acetylated D ‐ and L ‐α‐mannosylacetaldehydes have been prepared and used as substrates to produce the corresponding cyanohydrins or cyanohydrin acetates with (2 S ) or (2 R ) configuration, respectively, at the cyanohydrin moiety. The ( R )‐oxynitrilase‐catalysed synthesis and lipase‐catalysed diastereomeric kinetic and dynamic kinetic resolutions were investigated. Sequential catalysis with almond meal [an economic source of ( R )‐oxynitrilase] and Burkholderia cepacia lipase was shown to be a straightforward method that yielded the four diastereomeric target cyanohydrins, the absolute configurations of which were confirmed by 1 H NMR analysis.