Access to 5,5'-diaryl substituted 4,5,4',5'-tetrahydro[3,3']bi-isoxazolyl 2,2'-dioxides, 4,5,4',5'-tetrahydro[3,3']bi-isoxazolyls and [3,3']bi-isoxazolyls via an initial ring-opening of 3,4-dinitrothiophene

Abstract

By means of an iodide-catalyzed nitrocyclopropane to 4,5-dihydroisoxazoline 2-oxide isomerization, the 1,1-dinitro-[1,1]bi(cyclopropyl)s 5, deriving from an initial ring-opening of 3,4-dinitrothiophene 1, can be stereospecifically converted into the bisnitronates 6. From these, successive N-oxide reduction [P(OMe) 3 /dioxane] and aromatization (DDQ/toluene) provide convenient access to the interesting 4,5,45-tetrahydro[3,3]bi-isoxazolyls 7, and [3,3]biisoxazolyls 8, respectively.