Group 16 atoms, nucleophilic substitution alkene-alcohol reactions

We want to convince you that this chemistry is useful and also that it works in more complicated molecules so we are going to describe in part the preparation of the antibiotic ofloxacin. The sequence starts with an aromatic compound having four fluorine atoms. Three are replaced sequentially by nucleophiles and the last is present in the antibiotic itself. The first reaction is a conjugate substitution of the ethoxy group marked in orange. An amino alcohol is used as the nucleophile and it is the more nucleophilic amino group (rather than the hydroxyl group) that adds to the alkene. 

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