Table 3. 2,5-Dimethylphenacyl (8, DMP) Photoremovable Group.

leaving group, X (protected species)	solvent	quantum yield, Φ	chemical yield of HX release (%)	kapp/s–1 a
Cl	benzene	0.1156a (0.12)54a		4.4 × 106 61
	methanol	0.7656a (0.78)54a		4.4 × 104 61
OC(=O)R (carboxylic acids)	benzene	0.18–0.2554b,57b	85–9554b	∼257b
	methanol	0.09–0.1457b	9254b	4.5 × 102 57b
OP(=O)(OR)2 (phosphates)	benzene	0.0954a		∼254a
	methanol	0.7154a	9454a	5 × 104 54a
OS(=O)2R (sulfonic acids)	benzene	0.16–0.1954a
	methanol	0.6854a	90–9354a	4 × 104 54a
OC(=O)OR (alcohols)	cyclohexane	0.36–0.5158	>7058	b
	methanol	0.09–0.2058		b
OC(=O)NR2 (amines)	cyclohexane	0.054–0.08959		b
	acetonitrile	0.035–0.07059	9759	b
	methanol	0.027–0.06159		b

^aAppearance rate constant of the leaving group, calculated as k_app = 1/τ_enol.

^bSlow, presumably <1 ms^–1.