Fig. 6. Chemo-enzymatic total syntheses of alkaloids published per year. The colours indicate the different chemo-enzymatic approaches as discussed in this review: (a) biocatalytic preparation of chiral building blocks (blue), (b) biocatalytic kinetic resolution, dynamic kinetic resolution, and deracemisation of alkaloids (green), (c) biocatalytic reduction of imines or iminium ions (purple), and (d) chemo-enzymatic syntheses that use enzymes for key asymmetric C–C and/or C–N bond formation (orange).