Nucleophilic vinylic substitution in bicyclic methyleneaziridines: SNVπ or SNVσ?

A stereodefined monodeuterated methyleneaziridine is shown to be prepared via coordinated reductive ring-opening of an alkynyl epoxide and diastereoselective tethered allene aziridination. Ring-opening of this aziridine with copper-based organometallics follows a pathway that results in stereoretentive substitution, replacing the exo-C-N bond with a corresponding C-C bond; this stereochemical outcome supports either an overall SNV pi mechanism or a C-N insertion/reductive coupling process.

Automated summary

A stereodefined monodeuterated methyleneaziridine was prepared by coordinated reductive ring-opening of an alkynyl epoxide and diastereoselective tethered allene aziridination. Subsequent reaction of this aziridine with copper-based organometallics results in stereoretentive substitution, suggesting either an SNV pi mechanism or a C-N insertion/reductive coupling process.