Dual Basicity and Nucleophilicity of Organosodium Reagents in Benzylic C-H Additions of Toluenes to Diarylethenes and Ketones.

Abstract

Profiting from the dualhigh basicity and nucleophilicity of organosodium complexes, here we report the stepwise lateral metalation of a wide range of alkyl arenes (MeAr), mediated by hydrocarbon-solubleNaCH2SiMe3.PMDETA (PMDETA =N,N,N',N'',N''-pentamethyldiethylenetriamine),followed by nucleophilic addition to olenfins of the newly generatedNaCH2Ar.PMDETA complexes. This method grants access to a range offunctionalisedhydrocarbons in excellent yields and can be upgraded to catalytic regimes when usingtrans-stilbene, a 10 mol% of the alkyl sodium base and toluene as a solvent. Extending this approach to aromatic ketones leads to the formation of stilbenes under mild reaction conditions, resulting from the deprotonative coupling of toluenes with ketones. Combining spectroscopic studies with the trapping andcharacterisationof key reaction intermediates, mechanistic insights have been gained, advancing the understanding of coordination effects in organosodium chemistry, and shedding light on their special reactivity profiles.