Dihydrolevoglucosenone (Cyrene™), a new possibility of an environmentally compatible solvent in synthetic organic electrochemistry.

Dihydrolevoglucosenone (DLG or Cyrene™) solvent is a green dipolar solvent produced from cellulose waste. Different studies have demonstrated that it can successfully replace dipolar solvents, such as N , N -dimethylformamide (DMF), N , N -dimethylacetamide (DMA) and N -methylpyrrolidinone (NMP), in a variety of chemical reactions. In this paper, the first application of DLG in organic electrosynthesis is described, with results of its use in the electrochemical reduction of benzophenone derivatives ( ca. E = -1.75 V vs. Ag/AgCl), as a greener alternative to other dipolar solvents with environmental concerns. Conductivity measurements show that the solvent presents conductivity and viscosity limitations that can be overcome by using EtOH as a cosolvent. The DLG/EtOH mixture resulted in a convenient solvent to carry out galvanostatic electroreductions of starting materials that exhibit high potential value. Furthermore, the reaction pathway (1e - or 2e - ) was found to be dependent on the supporting electrolyte used; TBABF 4 favored 2e - reduction to the corresponding alcohol (52-85%), whereas LiClO 4 promoted C-C pinacolic coupling (47-70%).