Metathesis of azomethine imines in the reaction of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with carbonyl compounds

An interaction of carbonyl compounds (isatins, 4-nitrobenzaldehyde) with azomethine imines generated by the diaziridine ring opening in 6-aryl-1,5-diazabicyclo[3.1.0]hexanes in the presence of BF₃·Et₂O as a catalyst induced the metathesis to other azomethine imines with the elimination of aldehydes ArCHO. New azomethine imines were trapped with diethyl acetylenedicarboxylate, otherwise they transformed to the corresponding pyrazolines due to a 1,4-H shift.