Oxidation of indole substrates by oxodiperoxomolybdenum-trialkyl(aryl) - phosphine oxide complexes

A series of oxodiperoxo molybdenum complexes MoO5.O=PR3.L, where R = Me, Et, Pr, Bu, or Ph, have been synthesized. The X-ray crystal structures for the complexes with triethylphosphine oxide and tripropylphosphine oxide as ligands were obtained. These complexes oxidize indoles to various indolone products depending on the substitution pattern of the indole substrate.