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

Abstract

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.