Electrophilic Activation of Silicon–Hydrogen Bonds in Catalytic Hydrosilations

Abstract

Hydrosilation reactions represent an important class of chemical transformations and there has been considerable recent interest in expanding the scope of these reactions by developing new catalysts. A major theme to emerge from these investigations is the development of catalysts with electrophilic character that transfer electrophilicity to silicon via Si-H activation. This type of mechanism has been proposed for catalysts ranging from Group 4 transition metals to Group 15 main group species. Additionally, other electrophilic silicon species, such as silylene complexes and η 3 -H2SiRR' complexes, have been identified as intermediates in hydrosilation reactions. In this Review, different types of catalysts are compared to highlight the range of hydrosilation mechanisms that feature electrophilic silicon centers, and the importance of these catalysts to the development of new hydrosilation reactions is discussed.

A Dicationic Bismuth(III) Lewis Acid: Catalytic Hydrosilylation of Olefins

“…We chose to investigate the hydrosilylation of olefins in the presence of catalytic amounts of 2 . Hydrosilylation of olefins is an important industrial process in the production of a variety of products including lubricants, coatings, cosmetics and adhesives , . Precious metal catalysts – Speier′s catalyst ([H 2 PtCl 6 ].H 2 O), Karstedt′s catalyst [Pt(O) compound bearing vinyl‐siloxane ligands] and Markó's catalyst (modified Karstedt catalyst bearing NHC ligand) have been traditionally employed to carry out hydrosilylation of alkenes.…”

Taming the Cationic Beast: Novel Developments in the Synthesis and Application of Weakly Coordinating Anions

“…[416][417][418][419] WCA ] À )f eaturing aS i ÀH bond have been shown to be capable of the hydrosilylation of alkenes through an unusual mechanism. [422][423][424] More recently,t he ferrocenyl-substituted silylium ion [FcSi( t Bu)-(Me)] + supported by the [B-(C 6 F 5 ) 4 ] À ion has even been shown to effect the reduction of ketones without competing deoxygenation pathways. [420,421] Ther elated neutral Lewis acid B(C 6 F 5 ) 3 remains the most widely utilized main-group catalyst for the hydrosilylation of aromatic aldehyde,k etone,a nd ester substrates.T he reaction mechanism has been shown, through aseries of detailed studies,t op roceed through the activation of the SiÀHb ond by the B(C 6 F 5 ) 3 Lewis acid not through the activation of the hydrosilylation substrate.…”

Highly Efficient Route for the Synthesis of a Novel Generation of Tetraorganofunctional Double‐decker Type of Silsesquioxanes

“…At the same time, chemists are looking for synthetic routes exploiting among others hydrosilylation reaction to obtain novel, functionalized Si-based reagents with a specific structure such as silsesquioxanes. [17][18][19][20][21][22][23][24][25][26][27] While hydrosilylation of olefins with silanes has been widely studied, [3,28] the reports on T 8 silsesquioxanes are limited [5,6,[29][30][31][32][33][34] and for double-decker systems of both closed (D 2 T 8 [4,19,25,[35][36][37] ) and opened (M 4 T 8 [38][39][40][41][42][43] ) structure even more scant. [5] Cage-like derivatives have driven much attention due to specific physicochemical properties (governed by the nature of their silicate rigid core and by the number and type of functional groups attached to it) affecting directions of their broad applications from material chemistry to medicine.…”