Hypercoordinate Organosilicon Complexes of an ONN′O′ Chelating Ligand: Regio- and Diastereoselectivity of Rearrangement Reactions in Si−Salphen Systems

Reactions of various organochlorosilanes with the salphen-like tetradentate (ONN′O′) ligand o-HO-p-MeO-C6H3C(Ph)N(o-C6H4)NCHC6H4-o-OH, bearing two chemically and sterically different imine moieties, provided insights into the regio- and diastereoselectivity of various rearrangement reactions. Whereas thermally driven allyl- and UV-induced phenyl-shift reactions from the Si to an imine carbon atom yield one diastereomer, hydride-shift reactions were found to be less diastereoselective; however, only the sterically less demanding salicylaldimine site was attacked in all these rearrangement reactions.