Propargylic oxidations catalyzed by dirhodium caprolactamate in water:: Efficient access to α,β-acetylenic ketones

Dirhodium(II) caprolactamate (1, Rh(2)(cap)(4)) with 70% w/w aqueous tert-butyl hydroperoxide (T-HYDRO) is a highly effective catalytic oxidation protocol for the selective C-H oxidation of alkynes to propargylic ketones. The oxidation occurs readily in aqueous solvent under mild conditions with an inexpensive and easily handled oxidant. alpha,beta-Acetylenic carbonyl compounds are formed in up to 80% isolated yield.