Mg(HSO₄)₂/SiO₂ as a Highly Efficient Catalyst for the Green Preparation of 2-Aryl-1,3-Dioxalanes/Dioxanes and Linear Acetals

Table 3

Comparison of our method with previous reported method in the synthesis of 4a.

Entry	Conditions (catalyst/temperature (°C)/solvent)	Time (min)	Yield (%)^a	[References]
1	Ionic liquid [SOClMIm]Cl/40/-	1200	80	[15]
2	In(OTf)3/80 (reflux)/Benzene	180	92	[18]
3	Multi-SO3H functionalized ionic liquids/25/-	180	96.5	[13]
4	SG-[(CH2)3SO3H-HIM]HSO4	90	95	[12]
5	Ionic liquid [TMPSA]HSO4/25/-	30	77	[14]
6	SiO2-SO3H/68 (reflux)/𝑛-hexane	60	58	[28]
7	Mg(HSO4)2/SiO2	10	98	This work