Table 5.

Intramolecular ²H KIEs measured in dichloromethane as a function of temperature, computed KIEs under assumptions of no stereoinversion and facile stereoinversion, and ratios of primary to secondary ²H KIEs for the two distinct transition structures. All structures used to compute KIEs were optimized in the presence of a polarizable continuum model for dichloromethane.

	-78 °C	-63 °C	-47 °C	-23 °C
2H KIE (Expt.)	2.82 ± 0.06	2.37 ± 0.05	2.22 ± 0.02	2.08 ± 0.07
2H KIE (Sim.)a	2.76	2.44	2.23	2.04
2H KIE (no inversion)	1.63	1.60	1.57	1.53
2H KIE (inversion)	1.89	1.81	1.74	1.65
(1°/2°) KIE (endo-TS1)	1.85	1.77	1.70	1.62
(1°/2°) KIE (exo-TS1)	2.00	1.90	1.82	1.72

^aComputed intramolecular KIE under the assumption of no stereoinversion at the stereogenic sulfur center with amplification factors of 2.3 and 2.6 for the imaginary frequencies corresponding to deuterium abstraction (k₁ and k₃) and protium abstraction (k₂ and k₄), respectively.