The Selective Reduction of Aromatic Compounds to Dihydro or Tetrahydro Products by an Electrochemical Method

Scalable and safe synthetic organic electroreduction inspired by Li-ion battery chemistry

“…1E; for a complete listing, see Supplementary Materials), of which select efforts are summarized in entries 1-4. (12,13,15,36,42,43,48) To help probe the functional-group tolerance of these prior works, we opted for phenyl ethanol (3) as a model substrate. The conditions reported by Kashimura (15) were chosen as a basis set from which to launch more extensive optimization (entry 4); however, the limitations of that state-of-theart were clearly demonstrated in that 3's alcohol moiety completely shut down reactivity under Kashimura's conditions.…”

“…1C). However, all of these reports exhibit narrow scope-Kashimura's method is limited to hydrocarbons-and they require procedures (e.g., continuous sonication) that are no more scalable than a purely chemical Birch reduction (12,13,15,(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47).…”

The role of supporting electrolyte during the electrocatalytic hydrogenation of aromatic compounds

“…In these experiments, the predominant product was the 1,4-dihydro derivative, with current efficiencies near 90%. When benzene was electrochemically reduced via solvated electrons on Pt in ethylenediamine saturated with LiCI, cyclohexadiene was produced in a divided cell [14], whereas cyclohexadiene and cyclohexane were synthesized in an undivided cell [15]. Pasquariello el al.…”

Partial Reduction of Aromatic Rings by Dissolving Metals and by Other Methods

“…It was found that in addition to the expected products (124) and (125) (the latter arising from isomerization of the 1,4-dihydro isomer), there was formed a 25% yield of a mixture of alcohol (126) and hydrocarbon (127).7 1 In a subsequent investigation, in which rapid quenching procedures were employed, a 3: 1 mixture of (124) and (125) was obtained, indicating that the previous overreduction had occurred during the quenching process. It was found that in addition to the expected products (124) and (125) (the latter arising from isomerization of the 1,4-dihydro isomer), there was formed a 25% yield of a mixture of alcohol (126) and hydrocarbon (127).7 1 In a subsequent investigation, in which rapid quenching procedures were employed, a 3: 1 mixture of (124) and (125) was obtained, indicating that the previous overreduction had occurred during the quenching process.…”