The reactions of O-electrophiles, such as organic peroxides, with carbon nucleophiles are an umpolung alternative to the common approaches to C−O bond formation. Nucleophilic substitution at the oxygen atom of cyclic diacyl peroxides by enol acetates with the following deacylation leads to α-acyloxyketones with an appended carboxylic acid in 28−87% yields. The effect of fluorinated alcohols on the oxidative functionalization of enol acetates by cyclic diacyl peroxides was studied experimentally and computationally. Computational analysis reveals that the key step proceeds as a direct substitution nucleophilic bimolecular (S N 2) reaction at oxygen (S N 2@O). CF 3 CH 2 OH has a dual role in assisting in both steps of the reaction cascade: it lowers the energy of the S N 2@O activation step by hydrogen bonding to a remote carbonyl and promotes the deacylation of the cationic intermediate.

Here, we first report the 2′-acyloxy-1,3-dicarbonyl compound construction in a three-component oxidative reaction of alkyl ketene dimer with cyclic diacyl peroxide and trimethyl orthoformate. The discovered synthesis allows us to form 2′-functionalized 1,3-dicarbonyl compounds instead of the common 2-functionalized moiety. The reaction between 4-butylidene-3-propyloxetan-2-one and cyclopropyl malonoyl peroxide proceeds in the presence of trifluoroacetic acid and trimethyl orthoformate at 120 °C for 1 h. The synthesized compound was characterized by NMR spectroscopy, mass spectrometry, and IR spectroscopy.