Self-supported chiral titanium cluster

Self-supported chiral titanium clusters were prepared by mixing the ligand and titanium alkoxide in anhydrous toluene, followed by addition of a small amount of water (Scheme 7.22). In some cases, the cluster was completely insoluble in the reaction medium, especially in the case of 30. The cyanation works well with this heterogeneous catalyst, which was reused many times with no significant loss of activity. Additional experiments revealed that no appreciable amount of chiral catalyst had leached into the solution and the enantioselectivity came only from the solid catalyst. 

Strecker reaction A robust heterogeneous self-supported chiral titanium cluster (SCTC) catalyst applied both in batch and continuous mode [44] enabled imine cyanation as well as a three-component Strecker reaction using the corresponding aldehydes and amines under continuous flow conditions in a PBR giving aminonitriles enantiomeric excess values of up to 98%. 

Seayad, A.M., Ramalingam, B., Chai, C.LL, Li, C., Garland, M.V., and Yoshinaga, K. (2012) Self-supported chiral titanium cluster (SCTC) as a robust catalyst for the asymmetric cyanation of imines under batch and continuous flow at room temperature. Chem. Eur. J., 18, 5693-5700. doi 10.1002/chem.201200528... 

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