Recent Advances in Catalytic Hydrosilylations: Developments beyond Traditional Platinum Catalysts

Abstract

Hydrosilylation reactions, which allow the addition of Si−H to C=C/C≡C bonds, are typically catalyzed by homogeneous noble metal catalysts (Pt, Rh, Ir, and Ru). Although excellent activity and selectivity can be obtained, the price, purification, and metal residues of these precious catalysts are problems in the silicone industry. Thus, a strong interest in more sustainable catalysts and for more economic processes exists. In this respect, recently disclosed hydrosilylations using catalysts based on earth‐abundant transition metals, for example, Fe, Co, Ni, and Mn, and heterogeneous catalysts (supported nanoparticles and single‐atom sites) are noteworthy. This minireview describes the recent advances in this field.

Electrochemical recycling of homogeneous catalysts

“…For example, platinum catalyzed hydrosilylation is a cornerstone for the organosilicon industry (10), with a market size valued at $1.1 billion USD in 2019. The recovery of homogeneous platinum catalysts from silane product mixtures is a prominent challenge in chemical manufacturing (9)(10)(11)(12), with the platinum from catalysts accounting for up to 30% of the production cost of silicones. The high viscosity and boiling points of hydrosilylation products make traditional recovery methods such as distillation extremely costly (9,10).…”

“…The high viscosity and boiling points of hydrosilylation products make traditional recovery methods such as distillation extremely costly (9,10). While there have been efforts to find earth-abundant alternatives such as Fe, Co, and Ni complexes (13)(14)(15)(16), platinum-based hydrosilylation catalysts still monopolize the industry due to their unmatched atomic efficiency and kinetics, despite the drawbacks (9,12). Similarly, palladium-catalyzed cross-coupling reactions have rapidly seen the leap from laboratory-scale organic chemistry to industrial synthesis (17)(18)(19).…”

Regio- and Enantioselective CuH-Catalyzed 1,2- and 1,4-Hydrosilylation of 1,3-Enynes

“…[23][24][25][26] Functionalization of 1,3-enyne, a type of readily available compounds widely used in organic synthesis, has emerged as a powerful method to construct allenyl-and propagyl-derivatives. [27][28][29] However, hydrosilylation reaction of 1,3-enynes remains underdeveloped, in contrast to the signi cant advances in the hydrosilylation of alkenes, [30][31][32][33][34] alkynes [35][36][37][38][39][40] and 1,3-dienes. [41][42][43][44][45][46][47][48][49][50] Such reactions can proceed through three main pathways, including 1,2-/3,4-, [51][52][53][54][55][56][57] and 1,4-hydrosilylations, [58][59][60][61][62] which makes control of regio-, stereo-, and enantioselectivity di cult (Fig.…”

Recent advances in photo- and electro-enabled radical silylation

“…Hydrosilylation of alkenes is probably one of the most powerful methods for the synthesis of organosilicon compounds. [22][23][24][25][26][27][28] In 2015, Fagnoni, Ravelli, and co-workers reported a tetrabutylammonium decatungstate (( n Bu 4 N) 4 [W 10 O 32 ], TBADT) catalyzed hydrosilylation of electron-poor alkenes 2 with trisubstituted silanes 1 (Scheme 3). 29 A wide range of electron-poor olefins, including acrylate, phenylvinyl sulfone, acrylonitrile and α,β-unsaturated ketone, all reacted smoothly.…”