Formation of Bifunctional Octasilsesquioxanes via Silylative Coupling and Cross-Metathesis Reaction

Abstract

Bifunctional silsesquioxanes create an attractive group of compounds with a wide range of potential applications, and recently they have gained much interest. They are known to be obtained mainly via hydrosilylation, but we disclose novel synthetic protocols based on different but complementary reactions, i.e., cross-metathesis (CM) and silylative coupling (SC). A series of cubic T8 type silsesquioxane derivatives with a broad scope of styryl substituents were synthesized in a one-pot procedure and characterized by spectroscopic and spectrometric methods. All of the new compounds can be obtained in a one-pot manner, which has an attractive impact on the synthetic procedure, as it is economic in terms of the isolation of intermediate products. Additionally, the methodology disclosed here enables the (E)-stereoselective introduction of styrenes derivative to the cubic T8 type core. The presented compounds can be interesting precursors for a further functionalization that may significantly increase the possibility of their application in the design and synthesis of new functional materials.

Co‐catalyzed Selective syn‐Hydrosilylation of Internal Alkynes

“…Significantly, the subject of Co‐catalyzed hydrosilylation for internal alkynes, especially symmetrical ones, was limited to a few examples up until now [32,33,38–46] . As far as we know, only four research groups have reported satisfactory results to date, specifically regarding diaryl and bis‐aliphatic symmetrical internal alkynes [34–37,39,43] . Herein, we report a first example of catalytic hydrosilylation of internal alkynes triggered by the combination of PNP‐Co catalyst and hydrosilanes.…”

“…However, due to the low availability of noble metals and rising prices of such catalysts, more and more researchers try to develop sustainable alternatives. Thus, the complexes of Ni, [19–21] Mn,, [22] Fe, [23–26] and Co [26–46] were recently intensively studied. Interestingly, for Co‐catalyzed hydrosilylation of alkynes, the phenomenon of an extraordinary ligand control over the reaction pathway offers to receive all of the plausible regio‐ and/or stereoisomers, e. g ., β‐( E )‐, [26,41–44] β‐( Z )‐, [45] and α‐vinylsilanes [33,35–44] .…”

“…Thus, the complexes of Ni, [19–21] Mn,, [22] Fe, [23–26] and Co [26–46] were recently intensively studied. Interestingly, for Co‐catalyzed hydrosilylation of alkynes, the phenomenon of an extraordinary ligand control over the reaction pathway offers to receive all of the plausible regio‐ and/or stereoisomers, e. g ., β‐( E )‐, [26,41–44] β‐( Z )‐, [45] and α‐vinylsilanes [33,35–44] . However, to the best of our knowledge, there were no protocols describing the use of the triazine‐based PNP‐Co catalysts in the hydrosilylation of alkynes.…”

A library of new bifunctional alkenes obtained by a highly regiodivergent silylation of 1,5-hexadiene

“…25,26 However, due to the possibility of easy activation of the multiple C-C bonds, there has recently been a signicant increase in interest in alkenylsilanes and their synthesis. Conventional routes to target compounds involve transformations of vinylsilanes via silylative coupling, 27,28 cross metathesis 29,30 and silyl-Heck coupling. 31,32 However, the hydrosilylation is still the most convenient and the most oen used synthetic tool allowing direct access to new organosilicon derivatives.…”

Metal-free synthesis of unsymmetric bis(thioesters)

“…Modification of two identical functional groups in a molecule generates selectivity problems. 9 Functionalization of (di/multi)thiols can be particularly challenging, due to a growing number of possible reaction products (Scheme 2).…”