We investigated solvent effects on the acid-catalyzed deallylation of organoallylsilane precursors to identify mild solâgel polymerization conditions. Organoallylsilanes are expected to be alternative precursors for preparation of functionalized organosilica hybrids but they undergo solâgel polymerization with difficulty due to their low reactivity towards hydrolysis. Solâgel polymerization of model organoallylsilane precursors was conducted in various organic solvents and deallylation was monitored by 1H NMR spectroscopy. The nature of the solvent was found to strongly influence the deallylation rate and a significant correlation was observed between reaction rate and solvent basicity, which suggests that proton activity is a key factor in enhancing the reaction rate. In particular, acetonitrile was found to most effectively enhance the rate, and it accelerated the formation of a spirobifluorene-bridged organosilica hybrid film from its allylsilane precursor under a mild acidic condition. This key finding can be generally utilized for the preparation of organoallylsilane-derived highly functionalized organosilica hybrids.
Meerwein's Reagent Mediated, Significantly Enhanced Nucleophilic Fluorination on Alkoxysilanes
作者:Toyoshi Shimada、Yogesh Jorapur
DOI:10.1055/s-0031-1290757
日期:2012.4
We developed a new facile method to fluorosilanes from alkoxysilanes using Meerwein’s reagent. Our protocol afforded fluorosilanes in excellent yields in various organic solvents including acetonitrile under mild reaction conditions at room temperature. We also proposed a reaction mechanism with the probable silyloxonium intermediates.
An Efficient Method for the Synthesis of Symmetrical Disiloxanes from Alkoxysilanes Using Meerwein's Reagent
作者:Toyoshi Shimada、Yogesh Jorapur
DOI:10.1055/s-0031-1290668
日期:2012.7
report here a new and efficient route to symmetrical disiloxanes from their corresponding alkoxysilanes using Meerwein’s reagent as mediator and potassium carbonate as additive under mild reaction conditions in acetonitrile. Our methodology is very simple, economic, and high yielding. We have also proposed a reaction mechanism with the plausible silyloxonium intermediates. We report here a new and efficient