Ring-expansion reaction of 1-hydroperoxy-16-oxabicyclo[10.4.0]hexadecane catalyzed by copper ions: Use in the synthesis of 15-pentadecanolide

Article abstract of DOI:10.1007/BF02503491

A catalytic procedure has been developed for the synthesis of 15-pentadecanolide (1) from readily available 1-hydroperoxy-16-oxabicyclo[10.4.0]hexadecane (2). The method is based on the reaction of hydroperoxide 2 with copper acetate (0.15-5 mol.%). Ring expansion occurred as a result of generation of tertiary bicyclohexadecyloxyl radicals 4 from hydroperoxide 2 under the action of Cu^I ions, β-scission of the radicals accompanied by regioselective cleavage of the bridge bond to form macrocyclic C-centered radicals 5, and their oxidation by Cu^II ions to (E)-11- and (E)-12-pentadecen-15-olides (6). The products obtained were converted into 15-pentadecanolide by subsequent catalytic hydrogenation over a Pd catalyst in a yield of more than 90% with respect to hydroperoxide 2.