PUB - Publikationen an der Universität Bielefeld

A sequential-type as well as a tandem-type chemoenzymatic flow cascade combining an organocatalytic aldol reaction and a biocatalytic reduction to form stereoselectively a 1,3-diol with two stereogenic centers were developed. Initially, a comprehensive screening of 24 alcohol dehydrogenases was carried out and the identified candidates were applied in different multistep flow cascades. All four stereoisomers of the desired 1,3-diol product are accessible via a sequential flow approach with product formation-related conversions of up to 76% over two steps, isolated yields of up to 64% and enantiomeric excess of >99% in all cases. In addition, a tandem-type flow process, performing both reaction steps simultaneously, was established leading to 51 % conversion with >99% ee and 8:1 d.r. and representing a combination of the fields of asymmetric chemo-catalysis, biocatalysis and flow chemistry.