3,4-disubstituted piperidines are common fragments in medicinal chemistry, and their syntheses often require laborious multi-step processes. Biocatalytic access to 4-hydroxy-nipecotic acid serves as a gateway to access various 3,4-disubstituted piperidine derivatives easily through consecutive radical cross-coupling reactions as outlined in Figure . For example, 8 is a highly active monoamine transporter ligand. In the previous synthesis (Figure ), addition of a Grignard reagent to an expensive unsaturated piperidine (6), followed by chiral resolution and epimerization delivers piperidine 7. Subsequent ester reduction, oxidation, Horner-Wadsworth-Emmons (HWE) reaction, and another ester reduction were required, delivering the target molecule in eight steps (of which only two steps were strategic). In contrast, biocatalytically derived enantiopure 18 can be enlisted in doubly decarboxylative cross coupling (dDCC) with 47