Catalyst-free carbosilylation of alkenes using silyl boronates and organic fluorides via selective C-F bond activation

Jun Zhou,Bingyao Jiang,Takanori Imai,Zhengyu Zhao,Yamato Fujihira,Norio Shibata

doi:10.1038/s41467-021-24031-w

Jun Zhou, Bingyao Jiang + Show 4 more

Open Access

https://doi.org/10.1038/s41467-021-24031-w

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Abstract

A regioselective carbosilylation of alkenes has emerged as a powerful strategy to access molecules with functionalized silylated alkanes, by incorporating silyl and carbon groups across an alkene double bond. However, to the best of our knowledge, organic fluorides have never been used in this protocol. Here we disclose the catalyst-free carbosilylation of alkenes using silyl boronates and organic fluorides mediated by tBuOK. The main feature of this transformation is the selective activation of the C-F bond of an organic fluoride by the silyl boronate without undergoing potential side-reactions involving C-O, C-Cl, heteroaryl-CH, and even CF3 groups. Various silylated alkanes with tertiary or quaternary carbon centers that have aromatic, hetero-aromatic, and/or aliphatic groups at the β-position are synthesized in a single step from substituted or non-substituted aryl alkenes. An intramolecular variant of this carbosilylation is also achieved via the reaction of a fluoroarene with a ω-alkenyl side chain and a silyl boronate.

Highlights

A regioselective carbosilylation of alkenes has emerged as a powerful strategy to access molecules with functionalized silylated alkanes, by incorporating silyl and carbon groups across an alkene double bond
The use of two independent reactants for the transitionmetal-catalyzed difunctionalization of alkenes has emerged as a powerful strategy to access molecules with multiple functional groups, by incorporating two new functional groups across an alkene double bond[1,2,3,4,5,6]
A wide variety of aryl fluorides and alkyl fluorides are smoothly incorporated into the alkenes via the cleavage of a C–F bond in the presence of silyl boronates to provide β-functionalized silyl alkanes in good to excellent yield, without any help of transitionmetal catalysis nor photoredox system

Summary

Introduction

A regioselective carbosilylation of alkenes has emerged as a powerful strategy to access molecules with functionalized silylated alkanes, by incorporating silyl and carbon groups across an alkene double bond. B Carbosilylation of alkenes with silyl boronates and organic fluorides via C-F bond activation (this work). Our recent report on the defluorosilylation of organic fluorides using silyl boronates and with or without a Ni catalyst[58] inspired us to undertake a much more challenging research topic: the difunctionalization of alkenes with aryl or alkyl fluorides in the presence of silyl boronates via C–F bond cleavage (Fig. 1b).

Results

Conclusion