In general, acetals are used as protecting group for aldehydes, ketones or diols. In addition, O,O-Mixed acetals are well known as synthetic equivalents of aldehydes or esters and are widely used in diverse synthetic organic reactions, such as the Mukaiyama aldol, Diels-Alder, and radical cyclization reactions. So we develop a highly selective, direct, and simple synthetic method for the synthesis of mixed monosilyl acetals from aldehydes. In particular, we successfully carry out chemoselective Mukaiyama aldol reactions with mixed monosilyl acetals, relying on the discriminative activation of the alkoxy group on the acetal by different oxophilic catalyst. Furthermore, this study investigates more accurate mechanism through detection of oxocarbenium ion analyzed by ESI-HRMS. Finally we proceed highly anti-selective Mukaiyama aldol reaction with (E)- and (Z)- mixture of silyl enol ether.