Electrochemical formal homocoupling of sec-alcohols

Beilstein J Org Chem. 2022 Aug 22:18:1062-1069. doi: 10.3762/bjoc.18.108. eCollection 2022.


Electrochemical pinacol coupling of carbonyl compounds in an undivided cell with a sacrificial anode would be a promising approach toward synthetically valuable vic-1,2-diol scaffolds without using low-valent metal reductants. However, sacrificial anodes produce an equimolar amount of metal waste, which may be a major issue in terms of sustainable chemistry. Herein, we report a sacrificial anode-free electrochemical protocol for the synthesis of pinacol-type vic-1,2-diols from sec-alcohols, namely benzyl alcohol derivatives and ethyl lactate. The corresponding vic-1,2-diols are obtained in moderate to good yields, and good to high levels of stereoselectivity are observed for sec-benzyl alcohol derivatives. The present transformations smoothly proceed in a simple undivided cell under constant current conditions without the use of external chemical oxidants/reductants, and transition-metal catalysts.

Keywords: alcohols; dimerization; electrooxidation; electroreduction; paired electrolysis.

Grants and funding

This work was supported by the Japan Society of Promotion for the Sciences (JSPS) Grant-in-Aid for Scientific Research (19K05459, 19K16317, and 18K06582). The spectral data were collected with the research equipment shared in the MEXT Project for promoting public utilization of advanced research infrastructure (Program for supporting introduction of the new sharing system JPMXS0422500320).