Synthesis of enantioenriched spirocyclic 2-arylpiperidines via kinetic resolution.

Kinetic resolution of N -Boc-spirocyclic 2-arylpiperidines with spiro substitution at C-4 was achieved with high enantiomeric ratios using the chiral base n -BuLi/sparteine. Cyclopropanation or metallaphotoredox catalysis were used to access the piperidines, which could be further functionalised without loss of enantiopurity, highlighting their use as potential 3D fragments for drug discovery.