Experimental rate constants for the reactions of Michael acceptors 1–5 with GSH at 20 °C in aqueous solution, pH 7.4.

Enone	Electrophilicity E	k GSH (M−1 s−1)	k exp 2 (M−1 s−1)	k exp 2/keqn (1)2
1a	−20.6	(9.34 ± 0.66) × 10−1, (4.3 × 10−1)a	33 (15)a	21 (9.3)a
1b	−22.1	3.33 × 10−3a	0.12a	1/1.9a
2a	−22.1	(1.18 ± 0.07) × 10−1, (3.4 × 10−1)b	4.2 (12)b	18 (52)b
4a	−20.7	(1.93 ± 0.09) × 10−2	0.69	1/2.0
4b	−19.4	(5.75 ± 0.40) × 10−1	21	2.8
5a	−21.8	(1.77 ± 0.17) × 10−1	6.3	18
5b	−19.5	1.43 ± 0.11	51	7.7

^aCalculated from kinetic data reported in ref. 19d.

^bCalculated from kinetic data in ref. 21b.