Titanium Tetrafluoride/L-Prolinol Catalyzed Enantioselective Allylation of Aromatic Aldehydes with Allyltrimethylsilane

Aldehydes undergo smooth conversion to give homoallylic alcohols with allyltrimethylsilane employing 10 mol% of titanium tetrafluoride as a Lewis acid in the presence of 10 mol% of L-prolinol in CH3CN/CH2Cl2 (8:2) for 2 h at room temperature. The presence of functionalities such as chloro, nitro and bromo is well tolerated in the presence of catalyst. The reaction proved to be of general nature with yields varying from moderate to excellent depending on the structure of aldehydes used to give enantiomerically enriched homoallylic alcohols. The reaction proceeds under mild condition with simple experimental procedures.