Efficient Functionalisation of Cubic Monovinylsilsesquioxanes via Cross‐Metathesis and Silylative Coupling with Olefins in the Presence of Ruthenium Complexes

Abstract

Monovinylheptaisobutylsilsesquioxane undergoes efficient cross-metathesis and silylative coupling with styrenes. Allyl derivatives were successfully tested in cross-metathesis in the presence of first generation Grubbs catalyst, while heteroatom-substituted vinyl derivatives (vinyl ethers, 9-vinylcarb-A C H T U N G T R E N N U N G azole) efficiently undergo silylative coupling catalysed by ruthenium hydride complexes. Both reactions proceed highly stereoselectively and lead to nearly quantitative formation of E isomers. Only when vinyl ethers are used does the reaction lead to a mixture of stereoisomers. Atmospheric pressure photoA C H T U N G T R E N N U N G ionisation has been successfully used for recording mass spectra of the functionalised silsesquioxanes.

A library of monoalkenylsilsesquioxanes as potential comonomers for synthesis of hybrid materials

“…Naturally, the first step was to perform the synthesis of title compounds via the hydrolytic condensation of trisilanol (1-3OH) or monosilanol (1-OH) with respective alkenyltrichlorosilane or alkenylchlorodimethylsilane (2). The general synthetic concept for condensation reaction of silanols with chlorosilanes is documented, but we performed additional studies on the impact of type of solvent, base and the stoichiometry of the reagents, etc., on the overall efficiency of the process [31][32][33].…”

“…1.1). The first step was a synthesis of respective monosilanol (1-OH), which precedes via standard condensation reaction conditions with SiCl 4 , followed by hydrolysis of the Si-Cl bond, described earlier [31][32][33]. However, during synthesis of 1-Ph-OH, we encountered some difficulties employing known hydrolysis conditions [35] (the acidic conditions seemed to favor intercondensation of two 1-Ph-OH molecules, which was verified by 29 Si NMR: − 68 ppm).…”

The first ruthenium-silsesquioxyl complexes – synthesis, structure and mechanistic implications in silylative coupling

“…The ruthenium-silsesquioxyl complex 3 was examined in the silylative coupling of selected styrenes with vinylheptaisobutylsilsesquioxane and its catalytic activity was compared to that of its parent complex [RuHCl(CO)(PPh 3 ) 3 ] 1 and the previously studied more reactive complex [RuHCl(CO)(PCy 3 ) 2 ] 7 (Scheme 4). 15 Selected data for 1 and 3 are presented in Table 1, entry 1. As indicated in this table, the silsesquioxyl catalyst 3 exhibits higher catalytic activity than catalyst 1.…”

Regioselective formation of β‐(E)‐ and α‐alkenylsilane moiety attached to silsesquioxane core via Pt‐ and Ru‐based hydrosilylation

“…These processes have been studied by various groups . In recent years, our research team has contributed to developing an efficient and stereoselective synthesis of alkyl‐ and alkenyl‐substituted cubic T 8 derivatives . New procedures for ethynylsiloxy‐substituted silsesquioxanes and their catalytic germylative coupling have also been developed …”