Synthesis of 4‑Silacyclohexan-1-ones and (4-Silacyclohexan-1-yl)amines Containing the Silicon Protecting Groups MOP (4-Methoxyphenyl), DMOP (2,4-Dimethoxyphenyl), or TMOP (2,4,6-Trimethoxyphenyl): Versatile Si- and C‑Functional Building Blocks for Synthesis

The 4-silacyclohexanones 1–6 were prepared in convenient multistep syntheses, starting from MeSi­(OMe)₃ and PhSi­(OMe)₃, respectively. Cleavage of the 4-methoxyphenyl (MOP), 2,6-dimethoxyphenyl (DMOP), and 2,4,6-trimethoxyphenyl (TMOP) protecting groups of 4–6 by treatment with HCl/Et₂O in CH₂Cl₂ at 20 °C gives the 4-chloro-4-silacyclohexanone 13. Reductive amination of 1–6 with NH₃ or i-PrNH₂ yields the respective (4-silacyclohexan-1-yl)­amines 7–12. Compounds 1–12 and all new precursors synthesized were characterized by elemental analyses (C, H, N) or mass spectrometric investigations (ESI-HRMS) and by NMR spectroscopic studies (¹H, ¹³C, ²⁹Si). Compounds 1, 3, 5, and 6 and the precursors (MeO)₂SiPh­(TMOP) (21) and (CH₂CH)₂SiPh­(TMOP) (27) were additionally characterized by single-crystal X-ray diffraction. Compounds 1–12 with their Si- and C-functional groups represent versatile building blocks for synthesis.