Übergangsmetall-katalysierte Additionsreaktionen von 3-Phenyl-2H-azirinen und Acetylencarbonsäureestern

Transition Metal Catalyzed Addition Reactions of 3-Phenyl-2H-azirines and Alkyl Acetylene Carboxylates In the presence of molybdenum hexacarbonyl, the 3-phenyl-2H-azirines 1 and 7 react with alkyl acetylene carboxylates 2 via the cleavage of the C, N-double bond to give 2H-pyrroles 5 or pyrrole 9 (Table), whose structures were deduced from the spectra data, in particular ¹³C-NMR. data. The 2H-pyrrole 5a was also obtained by treatment of a mixture of 1 and 2a with tungsten hexachloride. A tentative mechanism for the formation of the 2H-pyrroles is formulated.