All calculations were performed using the augmented correlation-consistent triple-zeta Dunning (aug-cc-pVTZ) basis set. Auxiliary basis sets supporting the resolution-of-identity (RI) approximation were also employed to reduce computational costs. For DFT calculations, the chainof-spheres algorithmic approximation (RIJCOSX) for Coulomb and Hartree-Fock exchange matrix computations was used, with the general Weigend JK (aug-cc-pVTZ/JK) auxiliary basis set being used alongside aug-cc-pVTZ. For MP2 calculations, the RI approximation for MP2 inte-grals was used, and the Hellweg (aug-cc-pVTZ/C) auxiliary basis set was used to support MP2 calculations. The RIJCOSX approximation for the Hartree-Fock step within MP2 was also employed using aug-cc-pVTZ/JK. In all calculations, the charge was set to -1 e and 0 e for anionic and neutral structures, respectively. All structures were close-shelled with no unpaired electrons, and the spin multiplicity was thus set to 1 in all calculations to represent the singlet state. Relaxed potential energy surface (PES) scans were conducted for both the C α -C β -S-C dihedral angle, Θ, and the S-C β bond length, r. For Θ, the reaction coordinate was varied from 0 • to 350 • with 10 • intervals, and the rest of the system was allowed to relax; the C α -C β -S-C dihedral angles of enolate intermediates and transition states are denoted as Θ min and Θ ‡ , respectively. For r, the reaction coordinate was varied from 1.8 Å to 2.7 Å with 0.025 Å intervals, and the rest of the system allowed to relax; the S-C β bond lengths of enolate intermediates and transition states are denoted as r min and r ‡ , respectively.