Fluorinated heterocycles, which are highly-sought after building blocks for the pharmaceutical and agrochemical industries, can be accessed in a single step by the intramolecular fluorocyclisation of alkenes. Although fluoraza reagents have been used successfully for the fluorocyclisations of unsaturated carboxylic acids, alcohols and amines, these electrophilic fluorinating reagents are expensive. Nucleophilic fluoride sources are much more attractive in terms of cost and for the preparation of 18F-labelled radiotracers for medical diagnostics. We have developed a new, air- and moisture- stable fluorinating reagent 1. The key feature of 1 is that it is prepared by nucleophilic fluorinations, but it can simulate electrophilic fluorinations to create new C-F bonds. In this presentation, I will report the intramolecular fluorocyclisations of unsaturated carboxylic acids to deliver lactones which contain a tertiary alkyl fluoride by an unusual cyclisation, aryl migration and fluorination cascade (Scheme 1). In contrast, the fluorolactonisation of the same substrate with a fluoraza reagent provided the lactone containing a primary alkyl fluoride and the advantage of fluoroiodane 1 is the ability to form new fluorinated heterocycles that cannot be prepared from the traditional electrophilic fluorinating reagents.

Intramolecular fluorocyclisations of alkenes with a stable hypervalent fluoroiodane reagent

253rd National Meeting (2017)

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