Hydroarylation of olefins catalysed by a dimeric ytterbium(II) alkyl.

Richardson, Georgia M; Douair, Iskander; Cameron, Scott A; Bracegirdle, Joe; Keyzers, Robert A; Hill, Michael S; Maron, Laurent; Anker, Mathew D · Nat Commun · 2021

basic_science · Level V

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Abstract

Although the nucleophilic alkylation of aromatics has recently been achieved with a variety of potent main group reagents, all of this reactivity is limited to a stoichiometric regime. We now report that the ytterbium(II) hydride, [BDI<sup>Dipp</sup>YbH]<sub>2</sub> (BDI<sup>Dipp</sup> = CH[C(CH<sub>3</sub>)NDipp]<sub>2</sub>, Dipp = 2,6-diisopropylphenyl), reacts with ethene and propene to provide the ytterbium(II) n-alkyls, [BDI<sup>Dipp</sup>YbR]<sub>2</sub> (R = Et or Pr), both of which alkylate benzene at room temperature. Density functional theory (DFT) calculations indicate that this latter process operates through the nucleophilic (S<sub>N</sub>2) displacement of hydride, while the resultant regeneration of [BDI<sup>Dipp</sup>YbH]<sub>2</sub> facilitates further reaction with ethene or propene and enables the direct catalytic (anti-Markovnikov) hydroarylation of both alkenes with a benzene C-H bond.