Selective Hydrosilylation of Alkynes with Octaspherosilicate (HSiMe₂O)₈Si₈O₁₂

Abstract

Comprehensive studies on platinum-catalyzed hydrosilylation of a wide range of terminal and internal alkynes with spherosilicate (HSiMe O) Si O (1 a) were performed. The influence of the reaction parameters and the types of reagents and catalysts on the efficiency of the process, which enabled the creation of a versatile and selective method to synthesize olefin octafunctionalized octaspherosilicates, was studied in detail. Within this work, twenty novel 1,2-(E)-disubstituted and 1,1,2-(E)-trisubstituted alkenyl-octaspherosilicates (3 a-m, 6 n-t) were selectively obtained with high yields, and fully characterized ( H, C, Si NMR, FTIR, MALDI TOF or TOF MS ES analysis). Moreover, the molecular structure of the compound (Me Si(H)C=C(H)SiMe O) Si O (3 a) was determined by X-ray crystallography for the first time. The developed procedures are the first that allow selective hydrosilylation of terminal silyl, germyl, aryl, and alkyl alkynes with 1 a, as well as the direct introduction of sixteen functional groups into the 1 a structure by the hydrosilylation of internal alkynes. This method constituted a powerful tool for the synthesis of hyperbranched compounds with a Si-O based cubic core. The resulting products, owing to their unique structure and physicochemical properties, are considered novel, multifunctional, hybrid, and nanometric building blocks, intended for the synthesis of star-shaped molecules or macromolecules, as well as nanofillers and polymer modifiers. In the presented syntheses, commercially available reagents and catalysts were used, so these methods can be easily repeated, rapidly scaled up, and widely applied.

Synthesis of Bio‐Based Silane Coupling Agents by the Modification of Eugenol

“…Platinum on carbon and PtO 2 (Table 1, entries 2–3) provided an almost quantitative conversion of 1a , giving a product 3a with 75% and 82% yield, respectively. Interestingly, the application of the PtO 2 /XPhos system (Table 1, entry 4), which has been previously reported to improve regioselectivity in the hydrosilylation of terminal alkynes, [51] resulted in a drop in the conversion (80%) and dramatically suppressed the reaction, giving product 3a with only 2% yield. Comparable results to PtO 2 and Pt/C were collected, using Karstedt's catalyst Pt 2 (dvs) 3 (73%).…”

Pt-Catalyzed Hydrosilylation of 1,3-Diynes with Triorganosilanes: Regio- and Stereoselective Synthesis of Mono- or Bis-silylated Adducts

“…The reactivity of silyl groups in desilylation or coupling processes leads to such products representing useful (enyne and diene) synthons in advanced organic synthesis. − The high tolerance of the hydrosilylation process to various functional groups, its simplicity, and diversity of the selectivity makes this method the first choice when the incorporation of a silyl group into the molecule is required. A number of scientific articles discuss the modification of monoynes with organosilicon compounds, − ,,, but the functionalization of conjugated 1,3-diynes, due to their much more complex structure, is far more difficult to control according to the regio- and stereoselectivity and is limited to just a few examples. − In the reported works, the hydrosilylation of conjugated diynes has been catalyzed by homogeneous or heterogeneous catalysts containing Ru, Rh, Ni, Pd, and Pt. − Depending on the type of the catalyst, reagents, and reaction conditions, substituted but-3-en-1-ynes, buta-1,3-dienes, allenes, or polymeric systems, cross-linked with silyl moieties, have been obtained. Several molecular catalysts (e.g., commercially used Pt Karstedt’s complex, Pt 2 (dvs) 3 (platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex)), as well as nanoparticles, have been examined in the hydrosilylation of conjugated diynes, but unfortunately the previously published articles do not contain detailed studies on the process conditions (reagents molar ratio, temperature, reaction time) or their efficiency.…”

“…27−36 The high tolerance of the hydrosilylation process to various functional groups, its simplicity, and diversity of the selectivity makes this method the first choice when the incorporation of a silyl group into the molecule is required. A number of scientific articles discuss the modification of monoynes with organosilicon compounds, [13][14][15][16]33,37,38 but the functionalization of conjugated 1,3-diynes, due to their much more complex structure, is far more difficult to control according to the regio-and stereoselectivity and is limited to just a few examples. 23−26 In the reported works, the hydrosilylation of conjugated diynes has been catalyzed by homogeneous or heterogeneous catalysts containing Ru, Rh, Ni, Pd, and Pt.…”

Synthetic Routes to Silsesquioxane-Based Systems as Photoactive Materials and Their Precursors

“…The photophysical and thermal features could enable the application of these compounds in OLEDs devices. Our group studied the hydrosilylation of olefins and alkynes with silsesquioxanes with one, four and eight reactive Si–H moieties, which constitute a valuable group of precursors used in the formation of photoactive materials [93,94,95,96,97].…”