Initiation in Photoredox C-H Functionalization Reactions. Is Dimsyl Anion a Key Ingredient?

BUDÉN, MARÍA E.; BARDAGÍ, JAVIER I.; PUIATTI, MARCELO; ROSSI, ROBERTO A.

JOURNAL OF ORGANIC CHEMISTRY

AMER CHEMICAL SOC

Año: 2017 vol. 82 p. 8325 - 8325

0022-3263

revious studies have reported a directarylation of unactivated arenes with ArX in the presence of a base (KOtBu or NaOtBu) and an organic additiveat high temperatures. Recently,we showed that this reaction could be carried out in the absence of additivesat room temperature, but employing UV-Vis light. However, details of mechanismsthat can use a photoinduced Base-promoted Homolytic Aromatic Substitutionreaction (photo-BHAS) have remained elusive to now. The present work exploresvarious mechanistic possibilities of the key electron transfer step (ET) of this reaction, in order toidentify a possible route for the formation of 1-adamantyl radicals from1-haloadamantanes (initiationstep). On the basis of photochemical and photophysicalexperiments, and computational studies, we propose an unprecedented initiationstep that replaces KOtBuas the key ingredient, which could also be applied to other ET reactionsperformed in DMSO. For the first time is reported that dimsylanion, formed from a str