Synthesis of titanium-containing helical silicates for catalytic oxidation of alkenes

A new series of titanium-containing helical silicates were prepared by doping of chiral sodium lactate in a sol–gel process. Characterizations revealed that the present titanium materials had good porosities, hexagonal symmetries, helical morphologies, as well as right-handed internal chiralities. Loading of chiral sodium lactate in preparation facilitated internal chiralities of synthetic products. In catalysis, the titanium materials showed moderate-to-excellent conversions, moderate-to-high stereoselectivities, and satisfactory recyclings for oxidation of aliphatic and aromatic alkenes by using solid oxidants such as iodobenzene diacetate and iodosylbenzene. Furthermore, both using ionic liquid as solvent and leaching of catalyst were studied. In general, titanium-containing chiral silicates were provided, and their applications in asymmetric catalysis were discussed too, which showed values on design of new efficient chiral catalysts.