Selective Hydrosilylation of Alkynes with Octaspherosilicate (HSiMe2 O)8 Si8 O12.

Abstract

Comprehensive studies on platinum-catalyzed hydrosilylation of a wide range of terminal and internal alkynes with spherosilicate (HSiMe2 O)8 Si8 O12 (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 (1 H, 13 C, 29 Si NMR, FTIR, MALDI TOF or TOF MS ES+ analysis). Moreover, the molecular structure of the compound (Me3 Si(H)C=C(H)SiMe2 O)8 Si8 O12 (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.