a, (S)-SEGPHOS bound to ruthenium. b, TADDOL-derived phosphate and its slanted orientation relative to the P-Ru-P plane. c, Catalyst system viewed from above. The catalyst’s conformational rigidity is in part due to a SEGPHOS phenyl group which occupies an empty quadrant of the TADDOL-derived scaffold (top-left), preventing phosphate rotation. d, Network of CH-π interactions. All structures are derived from optimized syn-π-allyl species, non-critical atoms omitted for clarity. M06/SDD-6-311G(d,p)-IEFPCM(acetone)//B3LYP/SDD-6-31G(d).