Oxidation of Alkynes by the HOF·CH₃CN Complex

Palladium on Carbon‐Catalyzed Synthesis of Benzil Derivatives from 1,2‐Diarylalkynes with DMSO and Molecular Oxygen as Dual Oxidants

“…These reagents or methods have several drawbacks, such as high toxicity and environmental burden, requirement of special equipments, low cost performance, and/or low yields. Dimethyl sulfoxide (DMSO), an inexpensive and widely used chemical, has been employed as an oxidant of the acid-, [15] Nbromosuccinimide- [16] or iodine-mediated [17] oxidation of 1,2-diarylalkynes. Although homogeneous transition metals, such as palladium(II) chloride [18] or iron-A C H T U N G T R E N N U N G (III) bromide, [19] have been reported to catalyze this transformation, [20,21] the use of a heterogeneous metal catalyst should be an attractive alternative due to its recoverability, reusability, and residual metal-free properties.…”

Direct addition of fluorine to arylacetylenes

“…The terms halogens in this context, however, was reserved almost exclusively to Cl 2 , Br 2 and occasionally also to XF (X = Br, I, OH) [5][6][7] but almost never to F 2 . Merritt was the first to add F 2 to some double and triple bonds [8], but his technique was such that nobody could repeat the experiments in the last 40 years.…”

Oxidation of benzoins to benzils in the presence of porphyrin sensitizers by air and sunlight or visible light

“…1,2-Diketones have been synthesized with different reagents, such as oxidation of 1,2-diols [37,38], oxidation of alkynes [39][40][41][42][43][44][45][46][47][48][49], oxidation of alkenes [50], oxidation of a-methylene ketones [51], rearrangement of a,b-epoxyketones [52][53][54], oxidation of vicinal dihaloalkenes [55], oxidation of epoxides [56], oxidation of 1,3-diols [57], and oxidation with molecular oxygen. They have been catalyzed by trichlorooxyvanadium [58], nickel-aluminum hydrotalcite [59], and chiral cobalt complex [60], while palladium-catalyzed oxidation of benzoins to benzils was achieved by using CsOH or K 2 CO 3 as a base [61][62][63].…”