The stereoselective organocatalytic addition of silyl enol ethers to aromatic aldehydes catalyzed by bisphosphoramides and the direct aldol reaction between ketones and aromatic aldehydes promoted by phosphinoxides in the presence of tetrachlorosilane were investigated by the DFT approach. The formation of different chiral cationic hypervalent silicon species was investigated by calculations. Investigation on Lewis base catalyzed Lewis acid mediated cross aldol reactions was also performed.