A series of aromatic cyanohydrins and their O silyl ethers have been synthesized by trimethylsilylcyanation of aromatic aldehydes using a catalyst generated in situ from optically active R (+) 1,1 2 bisnaphthol with n butyl lithium. Mandelonitrile was prepared in an isolated yield 70% with more than \{e.e.\} =60%. The effect of solvents and the amount of catalyst on enantioselectivity was also investigated.