Table 9. Comparison of SMA's catalytic efficiency for the synthesis of 3b with that of other catalytic systems.

Catalyst	Amount of catalyst	Yield (%)	Solvent	Time (min)	Temperature (°C)
[C4(DABCO)2](CuCl4)54	40 mg	95	—	7	110
p-TSA34	10 mol%	93	—	30	80
MgO55	5 mol%	75	MeCN	45	—
Fe3O4@IM56	30 mg	95	EtOH	15	Reflux
ZnFe2O4 (ref. 36)	10 mol%	96	MeOH	90	70
SMA (this work)	1 mol%	94	Water	15	rt