Effect of Ring Size and Methyl Substituents on LiBr-Catalyzed Rearrangements of Aryloxiranes

Article abstract of DOI:10.1021/jo00140a029

A series of indene 2,3-oxides and 3,4-dihydronaphthalene 1,2-oxides with methyl substituents on the oxirane ring was prepared, and the lithium bromide/acetonitrile catalyzed isomerization of these compounds to the corresponding 2-keto derivatives was examined.The presence of methyl substituents on the oxirane ring at the α carbon greatly enhanced the reactivity of the oxiranes relative to that of the unsubstituted compounds, while the presence of substituents at the β carbon reduced their reactivity.The effect of ring size was examined via a competition experiment involving indene 2,3-oxide and 3,4-dihydronaphthalene 1,2-oxide.The results of these studies suggest that the reagent can be used for selective transformation of aryloxiranes.