Azirines reactions with phosphines

In contrast to the well-defined photochemical behavior of 1-azirines the thermal reactions of these compounds have been studied less thoroughly (68TL3499). The products formed on photolysis of azirines can best be rationalized in terms of an equilibration of the heterocyclic ring with a transient vinylnitrene. Thus, products formed from the thermolysis of azirines are generally consistent with C—N cleavage. For example, the vinylnitrene generated from the thermolysis of azirine (149) can be trapped with phosphines (72CCS6S). 

Reactions of Isoxazoles. The kinetics of the isoxazole azirine rearrangement (336) -> (337) and those of the isoxazole oxazole transformation (338) (339) have been determinedPalladium(II) chloride-triphenyl-phosphine catalyses the cross-coupling of 4-iodo-3,5-dimethylisoxazole with styrene to yield the trans- compound (340). 3,5-Dimethylisoxazole can be lithiated in two stages, first at the 5-methyl group and then at the 3-methyl group. Isoxazoles add hypochlorous acid to form 4-chloro-2,3-dihydro-... 

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