Table 3. Second-order rate constants (k₂) for the reactions of Selectfluor™ 1 and NFSI 2 with nucleophiles 5a–d, in MeCN at 25 °C, and relative rates compared to the reactions of Selectfluor™ and NFSI with 4a–d.

Nucleophile	Electrophile	k 2 (25 °C)/M–1 s–1	k rel
5a-enol (R = H)	Selectfluor™ 1	4.37 × 10–2	1.0 (1.1) a
	NFSI 2	4.59 × 10–4	46
5b-enol (R = OMe)	Selectfluor™ 1	6.77 × 10–1	1.1 (1.1) a
	NFSI 2	6.11 × 10–4	4.4
5c-enol (R = Me)	Selectfluor™ 1	1.32 × 10–1	1.1
5d-enol (R = Cl)	Selectfluor™ 1	3.07 × 10–2	1.7
	NFSI 2	2.47 × 10–4	43

^aUsing k₂ values for reactions measured at 20 °C.