Acylvinyl azides

The (3-acylvinyl azides (46) lose N2 forming the isoxazole (47) in an anchimerically assisted concerted reaction (75AG(E)775, 78H(9)1207). The N,S-ylid (48) on heating undergoes cyclization to isoxazoles (49). 

Other workers have reported the thermal rearrangement to isoxazoles where 2-acyl-2/f-azirines are presumed to be intermediates. The thermally induced fragmentation reaction of acylvinyl azides (362) has been reported to result in the isolation of isoxazoles (365) as well as nitriles (366), presumably via a 2-acyl-2i/-azirine intermediate (363). ... 

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See also in sourсe #XX -- [ ]

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