Friedel-Crafts-Type Reactions with Electrochemically Generated Electrophiles from Donor-Acceptor Cyclopropanes and -Butanes

We describe a general electrochemical method to functionalize donor-acceptor (D-A) cyclopropanes and -butanes with arenes utilizing Friedel-Crafts-type reactivity. The catalyst-free strategy relies on the direct anodic oxidation of the strained carbocycles, which leads after C(sp(3))-C(sp(3)) cleavage to radical cations that act as electrophiles for the arylation reaction. Broad reaction scopes in regard to cyclopropanes, cyclobutanes, and aromatic reaction partners are presented. Additionally, a plausible electrolysis mechanism is proposed.

Automated summary

A new electrochemical method has been described for the functionalization of donor-acceptor cyclopropanes and cyclobutanes with arenes using Friedel-Crafts-type reactivity. The catalyst-free strategy relies on direct anodic oxidation of strained carbocycles, leading to the formation of radical cations that act as electrophiles for the arylation reaction. Broad reaction scopes for cyclopropanes, cyclobutanes, and aromatic reaction partners are presented, along with a proposed electrolysis mechanism.