A tripodal peptidic titanium phosphonate as a homochiral porous solid medium for the heterogeneous enantioselective hydration of epoxides

A porous, homochiral titanium-phosphonate material based on a tripodal peptide scaffold was used as a heterogeneous reaction medium for the enantioselective hydration (>99%) of styrene oxide. This titanium-phosphonate material, which was shown to contain confined chiral spaces, was prepared by polymerization of L-leucine onto a tris(2-aminoethyl)amine initiator, followed by capping with phosphonate groups and completed by non-aqueous condensation with titanium isopropoxide. Circular dichroism confirmed that the peptide tethers yielded a secondary structure. X-ray powder diffraction and transmission electron microscopy supported by a semi-empirical model showed the likely formation of a porous, lamellar material that was quantified by nitrogen adsorption.