Reaction of isoxazoles and isoxazolium salts with organometallic reagents. Synthesis of dihydroisoxazoles

Abstract

2,3- 2,5-, and 4,5-Dihydroisoxazoles have been selectively synthesized by reaction of isoxazoles with organo-lithium, -magnesium, and -aluminium reagents. Moreover, the reaction of benzoisoxazolium salts with highly basic organolithium compounds leads to phenylaziridines resulting from an unusual ring cleavage-closure process. A mechanism which accounts for all the experimental results is also given.