Reactions of Azirines. Carbene and Carbenoid Reactions

The reaction of 1-azirines 1 with dichlorocarbene (generated from phenyl(trichloromethyl)mercury) led to formation of ring opened (V-vinylimines 4. Hydrolysis of 4a produced propiophenone while treatment with azide ions gave a tetrazole. Attempts to prepare dichloroazabicyclobutanes 10, by addition of trichloromethide ions to several azirines 1 followed by base-catalyzed ring closure of the intermediate aziridines 6, led to azetines 9 except in the diphenyl substituted case 6c, when 13, a product of electrocyclic ring opening, resulted. The structure of azetines 9 was inferred from spectra including ¹³C nmr spectra and chemical conversions. The formation of azetines 9 from 6 most likely involves an azabicyclobutane intermediate 10. Chloroazetines 9 were further transtransformed to azetidinones 11 or methoxyazetine 12.