Organocatalytic Insertion of Isatins into Aryl Difluoronitromethyl Ketones

An
organocatalytic method that achieves insertion of isatins into
aryl difluoro­nitro­methyl ketones under mild conditions
is described. The reaction occurs in the presence of 20 mol % of DBU
and with 100% atom economy. A series of isatin derived difluoro­nitro­methyl
substituted tertiary alcohol benzoates and naphthoates were prepared
in 81–99% yield. The general synthetic usefulness of these
3-hydroxy­oxindole derivatives is demonstrated with the selective
reduction to fluorooximes.