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

Abstract

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.

Novel hexacoordinate organosilicon(IV) complexes of diethylenetriamine Schiff base with SiO2N3 skeleton

“…Wagler and co-workers [6][7][8][9][10] synthesized a large number of hypercoordinated complexes of silicon by using different salen and salphen type ligands and studied their reactivity. Recently, Bohme and his co-workers 11 also reported a new application of Wagler elimination by synthesizing a macrocyclic silicon enamine derivative.…”

Organosilicon and ‐germanium Hydrides in Catalyst‐Free Hydrometallation Reactions

“…The diastereoselectivity of the 1,2‐hydrosilylation was also studied. Synthesis of ligand 23 , containing two C(Ph)=N groups, and subsequent treatment with PhSiHCl 2 in the presence of Et 3 N provided a mixture of the two complexes 24A and 24B , each containing a chiral C H(Ph)N atom, in a 10:1 ratio (Scheme ) …”

Hexacoordinate Silicon Compounds with a Dianionic Tetradentate (N,N′,N′,N)-Chelating Ligand

“…Whereas SiCl 4 , PhSiCl 3 , and Ph 2 SiCl 2 were commercially available, (Anis) 2 SiCl 2 and (4-Me 2 N-C 6 H 4 )PhSiCl 2 were prepared from SiCl 4 and PhSiCl 3 , respectively, and suitable Grignard reagents (see Experimental Section). [7][8][9][10][11]18,19,[73][74][75][76][77] chelators, we have now explored silicon coordination chemistry with a dianionic tetradentate (N,N′,N′,N) chelator. Thus far, macrocyclic π-conjugated (porphyrine-and phthalocyanine-type) ligands [78][79][80][81] have been explored in silicon coordination chemistry (e.g., D [81]), and our study aims at building a bridge between these cyclic (N, …”

“…For diorganosilicon complexes with tetradentate salen-type ligands we have reported migration of one of the Si-bound substituents to an imine C-atom (with formation of pentacoordinate Si complexes) upon irradiation with UV (Scheme 4, left) [9,11,77], and we have observed similar behavior for silacycloalkanes with two (O,N) bidentate oxinate ligands (oxinate) 2 Si(CH 2 ) n (n = 3-6) [90]. The herein reported hexacoordinate diorgano Si complexes LSiPh 2 , LSi(Anis) 2 and LSiPh(4-Me 2 N-C 6 H 4 ) are also sensitive to light and have thus been synthesized in the dark.…”