Synthesis and characterization of a diaziridinium ion. Conversion of 3,4-dihydroisoquinolines to 4,5-dihydro-3 H -benzo(2,3)diazepines via a formal N-insertion process

A diaziridinium ion has been synthesized in high yield and its structure unambiguously confirmed by X-ray crystal analysis. The predicted N-transfer reactivity with olefins of this species was not observed. Instead, upon heating, the diaziridinium ion underwent ring opening to produce a dihydrobenzodiazepene product in good yield, thus achieving a formal N-insertion of the starting dihydroisoquinoline substrate. This process has been demonstrated on 11 total substrates.