Selectivity

Electrode

Organic chemistry

Combinatorial chemistry

Allene

Electrocatalyst

Catalysis

Physical chemistry

Chemistry

Chemoselectivity

Annulation

Cobalt

Electrochemistry

Regioselectivity

Photochemistry

ACS Catalysis

Versatile cobalt catalysis enabled electrochemical C–H activation with allenes. Thus, allene annulations were accomplished in terms of C–H/N–H functionalizations with excellent levels of chemoselectivity, site selectivity, and regioselectivity under exceedingly mild conditions. Detailed mechanistic studies were conducted, including reactions with isotopically labeled compounds, kinetic investigations, and in-operando infrared spectroscopic studies. Further, computational studies were supportive of a non-rate-determining C–H cleavage and gave key insights into the regioselectivity of the allene annulation. The practical utility of the user-friendly approach was furthermore highlighted by gram-scale electrocatalysis.

Electrooxidative Allene Annulations by Mild Cobalt-Catalyzed C–H Activation