A new selective approach to unsymmetrical siloxanes and germasiloxanes via O-metalation of silanols with 2-methylallylsilanes and 2-methylallylgermanes
A scandium(III) trifluoromethanesulfonate-catalyzed O-metalation of silanols with 2-methylallylsilanes and 2-methylallylgermanes leading to siloxane or germasiloxane bond formation under mild conditions with evolution of isobutylene is described.
Catalytic Approach to Germanium-Functionalized Silsesquioxanes and Germasilsesquioxanes
作者:Joanna Kaźmierczak、Grzegorz Hreczycho
DOI:10.1021/acs.organomet.7b00599
日期:2017.10.9
completely and partially condensed germanium-functionalized silsesquioxanes as well as germasilsesquioxanes, mediated by scandium(III) triflate. We provide a solution for introducing germyl functionalities into various types of silsesquioxanes under mild conditions with excellent yields. This methodology turns out to be a highly efficient and selective synthesis route to obtaining novel germanium-containing
Sc(OTf)(3)-catalyzed coupling reaction of silanediols with 2-methylallylsilanes and germanes leading to SiO-Si or SiO-Ge bond formation with the evolution of isobutylene is described. Diisopropyl-substituted silanediols of the general formula HO(i-Pr)(2)Si[OSi(i-Pr)(2)](n)OH (n = 0,1) have been successfully functionalized by using 2-methylallylsilanes or 2-methylallylgermanes in the presence of scandium trifluoromethanesulfonate to yield new linear tri- and tetrasiloxanes or germasiloxanes under mild conditions. The reaction can be readily extended to the synthesis of high molecular weight polysiloxanes by using di(methylallyl)silane as a metalating agent. Unsaturated oligosiloxane products have been used as substrates for further functionalization via catalytic silylative coupling and hydrosilylation reactions:
O-Metalation of silanols and POSS silanols over Amberlyst-15 catalyst: A facile route to unsymmetrical siloxanes, borasiloxanes and germasiloxanes
作者:Krzysztof Kuciński、Grzegorz Hreczycho
DOI:10.1016/j.ica.2019.03.025
日期:2019.5
A simple and highly practical Amberlyst-catalyzed direct O-metalation of silanols, POSS silanols and alkoxy-silanes under mild conditions is proposed. This protocol can be applied to the synthesis of a wide range of important organosilicon derivatives such as siloxanes, germasiloxanes, borasiloxanes and functionalized silses-quioxanes. It is worth noting that Amberlyst-15 can be reused for further experiments and its catalytic activity in this process is well-preserved for several recycling steps.
Metal triflate-mediated coupling of allylgermanes with thiols: a facile route to thiogermanes
作者:K. Kuciński、P. Pawluć、G. Hreczycho
DOI:10.1039/c5dt01734c
日期:——
A novel coupling reaction of thiols with (2-methylallyl)germanes catalyzed by metal triflates has been developed.