Tandem electrocatalytic aziridination – ring expansion of simple aromatic olefins using ammonia and carbon dioxide

Abstract

N-heterocycles are prominent structural motifs frequently occurring in organic synthesis and applications. Therefore, straightforward and green synthesis methods using common starting materials like alkenes are highly desired. Here, the metal-free electrochemical coupling of aromatic olefins with NH₃ and CO₂ or CS₂ in a telescoped sequence is reported, forming 2-oxazolidinones or 2-thiazolidinethiones. The reaction proceeds via a N–H aziridine, which subsequently undergoes ring expansion with CO₂ or CS₂. Both steps are mediated by the same simple iodide catalyst and total yields of up to 91% referring to the alkene are achieved with excellent regioselectivities. This sustainable reaction using readily available materials possesses an excellent atom efficiency with only H₂ as a potentially useful by-product.