An Amplified Ylidic “Half-Parent” Iminosilane LSiNH

The
reaction of LSiBr­(NH2) (4) (L = CH­[(CCH2)­CMe­(NAr)2]; Ar = 2,6-iPr2C6H3) with lithium bis­(trimethylsilyl)­amide
in the presence of pyridine or 4-dimethylaminopyridine (DMAP) resulted
in the activation of the α C–H bond of pyridine or DMAP,
affording the products LSi­(dmap)­NH2 (6) and
LSi­(pyridine)­NH2 (7a), respectively. Remarkably,
this metal-free aromatic C–H activation occurs at room temperature.
The emerging aminosilanes were isolated and fully characterized. Isotope
labeling experiments and detailed DFT calculations, elucidating the
reaction mechanism, were performed and provide compelling evidence
of the formation of the “half-parent” iminosilane 1, LSiNH, which facilitates this transformation due
to its amplified ylidic character by the chelate ligand L. Furthermore,
the elusive iminosilane 1 could be trapped by benzophenone
and trimethylsilylazide affording the corresponding products, 8 and 9, respectively, thereby confirming its
formation as a key intermediate.