An Electroreductive Approach to Radical Silylation via the Activation of Strong Si–Cl Bond

Abstract

The construction of C­(sp3)–Si bonds is important in synthetic, medicinal, and materials chemistry. In this context, reactions mediated by silyl radicals have become increasingly attractive but methods for accessing these intermediates remain limited. We present a new strategy for silyl radical generation via electroreduction of readily available chlorosilanes. At highly biased potentials, electrochemistry grants access to silyl radicals through energetically uphill reductive cleavage of strong Si–Cl bonds. This strategy proved to be general in various alkene silylation reactions including disilylation, hydrosilylation, and allylic silylation under simple and transition-metal-free conditions.

Unlocking the Potential of High-Throughput Experimentation for Electrochemistry with a Standardized Microscale Reactor

“…optimizing the current with a graphite cathode would result in the highest yield of 89%). Furthermore, the successful demonstration of this reaction showcases the HTe -Chem's compatibility with moisture sensitive, highly reducing conditions (-3.1 V vs. SCE or lower associated with the reduction of trimethylsilyl chloride 37 ).…”

“…The HTe -Chem presents precisely such capabilities, which we demonstrate in the further optimization of a reductive allylic silylation reaction recently developed in the Lin lab. 37 By screening four currents with six cathode materials, we obtained the desired allylsilane (4) in a highest yield of 98% using platinum cathodes, representing a 23% increase over the original optimal 75% yield obtained on 1 mmol scale with a graphite cathode (Figure 2). Intriguingly, use of stainless steel and platinum cathodes furnished the highest yields at 1.5-2.0 mA, whereas employment of graphite cathodes provided high yields at 0.5-1.0 mA.…”

Unlocking the Potential of High-Throughput Experimentation for Electrochemistry with a Standardized Microscale Reactor

“…The HT e – Chem presents precisely such capabilities, which we demonstrate in the further optimization of a reductive allylic silylation reaction recently developed in the Lin lab. 40 This reaction is proposed to undergo an ECEC mechanism wherein trimethylsilyl chloride is first directly reduced to a trimethylsilyl radical, which adds to an allylether ( 3 ) to generate a carbon-centered radical. This radical is further reduced to a carbanion and subsequently eliminates phenolate to deliver the allyl silane ( 4 ).…”

Electrophotocatalytic Si–H Activation Governed by Polarity-Matching Effects

“…[40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] However, in comparison with carbon radicals, the electrochemical generation of silyl radicals remains largely unexplored. Recently, Lin and coworkers 56 reported an elegant electroreductive approach to obtain silyl radicals from Si-Cl-containing compounds using Mg as a sacrificial anode.…”