Reduction of 2-H-substituted pyrrolinium cations: the carbon–carbon single bond in air stable 2,2′-bipyrrolidines as a two-electron-source

Reduction of 2-H-substituted pyrrolinium cations via initially formed secondary radicals results in either dimerisation or H-abstracted products, while the outcome depends on the N-substituents. The resultant central carbon-carbon single bond in the dimerised 2,2'-bipyrrolidine derivatives can be oxidised chemically and electrochemically. The notably air and moisture-stable dimers were subsequently utilised as a source of two electrons in various chemical transformations.