An Efficient Synthesis of Phenols via Oxidative Hydroxylation of Arylboronic Acids Using (NH₄)₂S₂O₈

Table 1

Effects of the solvent and temperature on the hydroxylation of 1a ^a.

Entry	Solvent	Temperature (°C)	2a yield^b (%)
1	Toluene : H2O 6 : 1	50	23
		80	53
2	Dioxane : H2O 6 : 1	50	28
		80	47
3	Acetone : H2O 6 : 1	50	33
		80	52
4	AcCN : H2O 6 : 1	50	30
		80	45
5	MeOH : H2O 6 : 1	50	32
		80	65
6	H2O	50	4
		80	13

aReactions conditions: 1a (0.41 mmol), (NH₄)₂S₂O₈ (1.0 equiv.), solvent 3 mL, and 24 h. ^bYield determined by ¹H NMR.