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.