A successful strategy for the construction of novel isomeric aza-analogues 13. HCl and 14. HCl of natural jaspine B was developed by constructing a vicinal diamino motif via a sequential Overman rearrangement, followed by a pyrrolidine core formation through SN2 type cyclisation. The olefin cross metathesis reaction was selected to incorporate the alkyl side chain unit. Based on an antiproliferative/cytotoxic evaluation study, it was observed that the final products display significant potency on Jurkat and HeLa cell lines, with IC50 values in the low micromolar range. Display omitted •Synthesis of novel aza-analogues of jaspine B was achieved.•The used strategy relied on sequential and simple 3,3-sigmatropic rearrangements, the OCM reaction and SN2 cyclisation.•The stereochemistry of key substructures was determined via crystallographic analysis.•The target pyrrolidines exhibit an ability to inhibit cancer cell proliferation.