Mesoporous Al-MCM-41 molecular sieve with Si/Al ratio equal to 12.5 was synthesized under hydrothermal condition using cetyltrimithylaminonium bromide (CTAB) as surfactant. This solid was characterized using several techniques e.g. powder X-ray diffraction (XRD), N-2 adsorption-desorption, FT-IR, TG/DTG and pyridine adsorption-desorption followed by IR spectroscopy. The catalytic performance of Al-MCM-41 catalyst as Lewis acid was used without treatment and was compared with TiCl4 in the allylation of aromatic aldehydes with allyltrimethylsilane. The results showed that in presence of Al-MCM-41, homoallyl silyl ether is obtained regardless of the nature of aromatic aldehydes at a temperature of 35 degrees C. When TiCl4 was used, the reactions require temperature of -85 degrees C and all the products obtained were due to the diallylation. To explain this different allylation in the presence of the Al-MCM-41 or TiCl4, two plausible reaction mechanisms are proposed. The Al-MCM-41 was used in four consecutive experiments without important loss of activity, confirming it stability. Finally, a new method for preparing single allylation in the short timeframe and mild conditions are presented. (C) 2016 Elsevier B.V. All rights reserved.