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

摘要

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/Et_2O in CH_2Cl_2 at 20 °C gives the 4-chloro-4-silacyclohexanone 13. Reductive amination of 1?6 with NH_3 or i-PrNH_2 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, ~(13)C, ~(29)Si). Compounds 1, 3, 5, and 6 and the precursors (MeO)_2SiPh- (TMOP) (21) and (CH_2＝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.