Hydrosilylation of RN=CH Imino‐Substituted Pyridines without a Catalyst

Abstract

Treatment of the neutral pyridine-based ligands L -L , bearing either one or two RN=CH imine moieties {where L and L are N,N-chelating ligands 2-(RN=CH)C H N (R=Ph (L ) or R=2,4,6-Ph C H (L )) and L is the N,N,N-chelating ligand 2,6-(RN=CH) C H N (R=2,6-iPr C H )}, with HSiCl yielded N→Si-coordinated silicon(IV) amides 2-{Cl SiN(R)CH }C H N (1, R=Ph; 2, R=2,4,6-Ph C H ) and 2-{Cl SiN(R)CH }-6-(RN=CH)C H N (3, R=2,6-iPr C H ). The organosilicon amides 1-3 are the products of spontaneous hydrosilylation of the RN=CH imine moiety induced by N→Si coordination of the proposed N,N-chelated chlorosilanes L →SiHCl (1 a), L →SiHCl (2 a), and L →SiHCl (3 a). Furthermore, the reaction of L with an excess of HSiCl provided the intramolecularly coordinated chlorosilicon diamide cyclo-{(C H N)-1,3-(CH NR) }SiCl (4) (R=2,6-iPr C H ) as the product of spontaneous reduction of both RN=CH imine moieties. The compounds have been characterized by NMR spectroscopy (1-4) and single-crystal X-ray diffraction analysis (1, 3, and 4). The mechanism of the hydrosilylation of the second RN=CH imine moiety in 3 by an excess of SiHCl has also been studied. The experimental work is supplemented by DFT calculations.

(N),C,N‐Coordinated Heavier Group 13–15 Compounds: Synthesis, Structure and Applications

“…These studies provided background for the synthetic protocol of the hydrosilylation of the imino‐ substituted pyridines by HSiCl 3 without the catalyst . The set of substituted imino‐pyridines was reduced to give unsymmetrically substituted pyridine‐based secondary amines (Scheme ).…”

Organosilicon and ‐germanium Hydrides in Catalyst‐Free Hydrometallation Reactions

“…After hydrolysis of the parent silicon amides, the corresponding unsymmetrically substituted secondary amines were prepared. This is a fairly straightforward protocol for the synthesis of unsymmetrically substituted pyridine‐based secondary amines without any requirement for strong reductants such as LiAlH 4 (Scheme ) …”

Synthesis of N-Heterocycle Substituted Silyl Ligands within the Coordination Sphere of Iron

“…Here we investigate the synthesis of a range of unusual silyl ligands incorporating pyrrolyl and indolyl substituents by nucleophilic substitution on the Fe-bound SiCl 3 fragment. Constructing complex silyl ligands in the coordination sphere of the metal avoids the intermediacy of hydrosilaneswhich can be subject to undesired rearrangements − and reactive silanides. We show that such substitution reactions are possible both on the neutral Fe­(II) complex Cl 3 Si–FeCp­(CO) 2 ( 1 ) and on the Fe(0) anion Cl 3 Si–Fe­(CO) 4 – ( 2 ), the latter being conveniently generated by deprotonation of the corresponding neutral Fe­(II) hydride ( 3 , Chart ).…”