Mechanistic Insight into the Halogen Dance Rearrangement of Iodooxazoles

Abstract

The lithium diisopropylamide mediated halogen dance reaction of 5-iodooxazoles to generate 4-iodooxazoles was studied. The mechanism of the reaction was investigated and compared to the reported mechanism for the halogen dance rearrangement of 5-bromooxazoles. Reaction conditions were optimized and yields of iodooxazole were improved to a synthetically useful level. The use of 2-(butylsulfanyl)-5-bromooxazole as an organic catalyst turned out to be the cornerstone for the success of this reaction.

Key words

halogen dance - oxazoles - halides - heterocycles - lithiation

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