Tandem Reactions of 1,2,4-Oxadiazoleswith Allylamines

A reaction of 3-chloro-1,2,4-oxadiazoles with allylamine and diallylamine has been investigated. 3,3a,4,5-Tetrahydroisoxazolo[3,4-d]pyrimidinesare produced through a tandem ANRORC/[3þ2]cycloaddition pathway consisting of the addition of allylamine to the 1,2,4-oxadiazole, followed byring opening, nitrone formation, and finally cycloaddition. 3-N-Allylamino-1,2,4-oxadiazoles were also obtained as minor products through aclassical SNAr. Conversely, a reaction with diallylamine produces 3-N,N-diallylamino-1,2,4-oxadiazole and imidazoline through tandem SNAr/aziridination and nucleophilic ring opening.