Synthesis of Silicon-Functionalized (Silylmethyl)silanes and α,ω-Dichlorocarbosilanes Using the TMOP (2,4,6-Trimethoxyphenyl) Protecting Group: (TMOP)Me₂SiCH₂Cl and (TMOP)₂MeSiCH₂Cl as Reagents To Introduce the ClMe₂SiCH₂, MeOMe₂SiCH₂, or Cl₂MeSiCH₂ Group by Nucleophilic Substitution at Silicon

Abstract

In this study, the synthetic potential of the 2,4,6-trimethoxyphenyl (TMOP)-substituted (chloromethyl)silanes (TMOP)Me 2 SiCH 2 Cl (1) and (TMOP) 2 MeSiCH 2 Cl (2) for the preparation of Si-functionalized (silylmethyl)silanes and α,ω-dichlorocarbosilanes (with skeletons consisting of alternate carbon and silicon atoms) was investigated. Compounds 1 and 2 were used as reagents to introduce the ClMe 2 SiCH 2 , MeOMe 2 SiCH 2 , or Cl 2 MeSiCH 2 group by nucleophilic substitution at silicon. The three-step synthetic method involves the (i) transformation of 1 and 2 into (TMOP)Me 2 SiCH 2 MgCl, (TMOP)-Me 2 SiCH 2 Li, (TMOP) 2 MeSiCH 2 MgCl, and (TMOP) 2 MeSiCH 2 Li, respectively, (ii) reaction of these nucleophiles with chloro-or methoxysilanes, and (iii) subsequent selective cleavage of the TMOP protecting group with HCl/Et 2 O or MeOH/[CF 3 COOH]. Using this method, the following compounds were prepared: ClMe 2 SiCH 2 SiMe 3 (3), ClMe 2 SiCH 2 SiMe 2 Cl (4), ClMe 2 SiCH 2 SiMeCl 2 (5), ClMe 2 SiCH 2 SiCl 3 (6), ClMe 2 SiCH 2 Si-(OMe) 3 (7), MeOMe 2 SiCH 2 Si(OMe) 3 (8), Cl 2 MeSiCH 2 SiMe 3 (9), Me 2 Si(CH 2 SiMe 2 Cl) 2 (10), and Me 2 Si-(CH 2 SiMe 2 CH 2 SiMe 2 Cl) 2 (11).

Si- and C-Functional Organosilicon Building Blocks for Synthesis Based on 4-Silacyclohexan-1-ones Containing the Silicon Protecting Groups MOP (4-Methoxyphenyl), DMOP (2,6-Dimethoxyphenyl), or TMOP (2,4,6-Trimethoxyphenyl)

“…In continuation of these studies, we have now succeeded in synthesizing a series of new 4-silacyclohexan-1-ones ( 1a – 1c ), 4-silacyclohexan-1-one oximes ( 2a – 2c ), 1,4-azasilepan-7-ones ( 3a – 3c ), 1,4-azasilepanes ( 4a – 4c ), and 2-bromo-4-silacyclohexan-1-ones ( 5a and 5b ) that contain the silicon protecting groups MOP (4-methoxyphenyl), DMOP (2,6-dimethoxyphenyl), or TMOP (2,4,6-trimethoxyphenyl). In previous studies, we have demonstrated that these three methoxy-substituted phenyl groups can be easily removed from the silicon atom of a given MOP-, DMOP-, or TMOP-silane via protodesilylation under very mild conditions to give the corresponding chloro- or methoxysilane . Thus, compounds 1a – 1c , 2a – 2c , 3a – 3c , 4a – 4c , 5a , and 5b can be regarded as versatile building blocks for synthesis that can undergo (i) a variety of transformations at their C-functional group and (ii) selective cleavage reactions of their Si–MOP, Si–DMOP, and Si–TMOP moieties.…”

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

“…In continuation of these studies, we have now succeeded in synthesizing a series of new 4-silacyclohexanones and (4-silacyclohexan-1-yl)amines that contain the silicon protecting groups MOP (4-methyoxyphenyl), DMOP (2,4-dimethoxyphenyl), or TMOP (2,4,6-trimethoxyphenyl). In previous studies, we have demonstrated that these protecting groups can be easily removed from the silicon atom via protodesilylation under mild conditions . Therefore, the Si–MOP, Si–DMOP, and Si–TMOP moieties can also be regarded as Si-functional groups.…”