benzaldehyde (in DMSO)

E Param.: -12.90

Only 1 reference nucleophile was used to determine the E parameter. Determined from the kinetics of an epoxidation reaction with a carbanion (ArSO2CHCl-) and corrected by the splitting ratio of forward and backward reaction.

The previously reported E = -19.5 holds for the gross rate constant of the reversible attack of the S-ylide (4-NC-C₆H₄)CH=SMe₂ at PhCHO (JACS 2011, 133, 8240), in which the epoxide ring closure is rate-determining.