Frustrated-radical-pair-initiated atom transfer radical addition of perfluoroalkyl halides to alkenes

Abstract

Frustrated radical pairs (FRP) are expected to effectively combine radical chemistry and the synergistic effects of a Lewis acid (LA) and Lewis base (LB), but this area is still in its primary stage. Here, we present a strategy for the generation of the [PhN˙⁺Me₂][B(C₆F₅)₃˙⁻] FRP using B(C₆F₅)₃ as the LA and PhNMe₂ as the LB. This FRP can initiate the efficient atom-transfer radical addition (ATRA) of different perfluoroalkyl halides to a variety of alkenes, furnishing a series of fluoroalkylated compounds in high regioselectivity and high-to-excellent product yields. This method exhibits broad substrate scope, 100% atom economy and good functional group compatibility. Systematic mechanistic studies (i.e., radical inhibitor and radical clock studies) and detailed experimental data coupled with structural characterizations led to a proposed reaction mechanism.