The synthesis of novel tetradentate ligands derived from salen and their application in enantioselective silylcyanation of aldehydes

Two new tetradentate ligands derived from salen have been prepared and their titanium complexes are used as chiral catalysts in the enantioselective silylcyanation of aldehydes, which give the silyl ethers of cyanohydrins in moderate to good enantiomeric excesses.

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N,N′-bis[(R)-Phenyl(2-hydroxy-3,5-di-tert-butylbenzyl)] cyclohexane-(1R,2R)-diamineC48H66N2O2[α]D20=-65.5 (c 0.01, CH2Cl2)

N,N′-bis[(R)-Phenyl (2-hydroxy-3-phenylbenzyl)] cyclohexane-(1R,2R)-diamineC44H42N2O2[α]D20=-212.7 (c 0.01, CH2Cl2)