Hydrosilylation of Alkenes Using a Hydrosiloxane as a Surrogate for Me₂SiH₂ and Catalyzed by a Nickel‐Pincer Complex

Abstract

We have developed a hydrosilylation reaction of alkenes using 1,1,3,3-tetramethyldisiloxane (TMDS) as a surrogate for Me 2 SiH 2 in the presence of NaOMe, catalyzed by a bench-stable nickelpincer complex supported by a monoanionic O,N,P-tridentate ligand. The reaction of styrene derivatives proceeds smoothly under mild reaction conditions to provide the hydrosilylated products in high yields with high Markovnikov selectivity. This protocol shows a wide substrate scope and is compatible with a wide range of functional groups. Secondary hydrosilanes are also suitable under the present reaction conditions and furnish the desired products in high yields.

(NHC)Ni(0)-Catalyzed Branched-Selective Alkene Hydrosilylation with Secondary and Tertiary Silanes

“…Without the presence of an aromatic moiety to stabilize a Ni-intermediate, the regiodivergent behavior may arise from steric hindrance provided by the alkyl substituent. This substrate-dependent reversal in selectivity is precedented in base-metal hydrosilylation systems. ,,,,,,,, …”

“…This substratedependent reversal in selectivity is precedented in base-metal hydrosilylation systems. 32,36,42,58,60,77,95,97,98 Illustrating the breadth of catalyst 1e to functionalize vinylarene derivatives, we further diversified the substrate scope by synthesizing a collection of electronically (3b−3e) and sterically modified diarylsilanes (3f−3i) and examined their hydrosilylation reactivity with 2a. The reactivity of 1e with modified silanes maintained outstanding selectivity for the branched product (l/b = 1:>99) and achieved moderate to high isolated yields (51−99%) to obtain products 4ab−4ae (electronic modification) and 4af−4ai (steric modification).…”

“…Even fewer examples enabling activation of 2°silanes have been reported. 32,52,57,58,60,98,99 To our knowledge, examples with 3°silanes are limited to the (pincer)Co-catalyzed hydrosilylation of 1-octene using (EtO) 3 SiH 73 and the ([P∼C]-chelate)Co-catalyzed hydrosilylation of styrene with Ph 3 SiH and Me(EtO) 2 SiH. 58 A significant challenge remaining in base-metal-catalyzed alkene hydrosilylation is the synthesis of branched hydrosilylation products using 3°silanes with alkyl-, aryl-, alkoxy-, or chloro-substituents (Figure 1b).…”

“…In the emergent field of base-metal-catalyzed branched-selective alkene hydrosilylation, noteworthy work achieving high regioselective control employs Mn, Co, ,,,, Fe, , Ni, − and Cu complexes that readily react with 1° silanes. Even fewer examples enabling activation of 2° silanes have been reported. ,,,,,, To our knowledge, examples with 3° silanes are limited to the (pincer)­Co-catalyzed hydrosilylation of 1-octene using (EtO) 3 SiH and the ([P∼C]-chelate)­Co-catalyzed hydrosilylation of styrene with Ph 3 SiH and Me­(EtO) 2 SiH . A significant challenge remaining in base-metal-catalyzed alkene hydrosilylation is the synthesis of branched hydrosilylation products using 3° silanes with alkyl-, aryl-, alkoxy-, or chloro-substituents (Figure b).…”

“…Catalysts composed of base metals ,− like Ni, − Mn, − Co, − and Fe ,− have been developed for linear-selective alkene hydrosilylation. As a congener of Pt, Ni is especially promising as a base-metal candidate for alkene hydrosilylation.…”