Paired electrolysis has a limited reaction scope for organic synthesis because it is often not compatible with reactions involving short-lived intermediates. We addressed this limitation using alternating current electrolysis (ACE). Using trifluoromethylation of (hetero)­arenes as a model reaction, we showed that the yield was improved from 13% using paired electrolysis to 84% using ACE. We have also developed a theory for guiding the rational design of reaction parameters for future applications of ACE.

2-Arylpyrrolidines occur frequently in bioactive compounds and thus methods to access them from readily available reagents are valuable. We report a copper-catalyzed intermolecular carboamination of vinylarenes with potassium N-carbamoyl-β-aminoethyltrifluoroborates. The reaction occurs with terminal, 1,2-disubstituted and 1,1-disubstituted vinylarenes bearing a number of functional groups. 1,3-Dienes are also good substrates and their reactions give 2-vinylpyrrolidines. Radical clock mechanistic experiments are consistent with the presence of carbon radical intermediates and do not support participation of carbocations.

Spirocyclic ethers can be found in bioactive compounds. This copper-catalyzed enantioselective alkene carboetherification provides 5,5-, 5,6- and 6,6-spirocyclic products containing fully substituted chiral carbon centers with up to 99 % enantiomeric excess. This reaction features the formation of two rings from acyclic substrates, 1,1-disubstituted alkenols functionalized with either arenes, alkenes, or alkynes, and clearly constitutes a powerful way to synthesize chiral spirocyclic ethers.

The oxidative coupling of alkyltrifluoroborates with heteroatom-tethered vinylarenes leads to a broad range of saturated oxygen and nitrogen heterocycles.