Radical Carbofluorination of Unactivated Alkenes with Fluoride Ions.

The copper-assisted radical carbofluorination of unactivated alkenes with fluoride ions is described. With [Cu(L3)F2]H2O (L3 = 4,4'-di(methoxycarbonyl)-2,2'-bipyridine) as the fluorine source and [Ag(DMPhen)(MeCN)]BF4 (DMPhen = 2,9-dimethyl-1,10-phenanthroline) as the chloride scavenger, the reaction of unactivated alkenes with CCl4 in acetonitrile provided the corresponding carbofluorination products in satisfactory yields. The protocol exhibited a wide functional group compatibility and broad substrate scope and could be extended to the use of a variety of activated alkyl chlorides other than CCl4. A copper-catalyzed fluorotrifluoromethylation of unactivated alkenes was then successfully developed with CsF as the fluorine source and Umemoto's reagent as the trifluoromethylating agent. A mechanism involving the fluorine atom transfer from Cu(II)-F complexes to alkyl radicals is proposed.

Silver-Catalyzed Decarboxylative Trifluoromethylation of Aliphatic Carboxylic Acids.

The silver-catalyzed decarboxylative trifluoromethylation of aliphatic carboxylic acids is described. With AgNO3 as the catalyst and K2S2O8 as the oxidant, the reactions of aliphatic carboxylic acids with (bpy)Cu(CF3)3 (bpy = 2,2'-bipyridine) and ZnMe2 in aqueous acetonitrile at 40 °C afford the corresponding decarboxylative trifluoromethylation products in good yield. The protocol is applicable to various primary and secondary alkyl carboxylic acids and exhibits wide functional group compatibility. Mechanistic studies reveal the intermediacy of -Cu(CF3)3Me, which undergoes reductive elimination and subsequent oxidation to give Cu(CF3)2 as the active species responsible for the trifluoromethylation of alkyl radicals.

Trifluoromethylation of Alkyl Radicals in Aqueous Solution.

The copper-mediated trifluoromethylation of alkyl radicals is described. The combination of Et3SiH and K2S2O8 initiates the radical reactions of alkyl bromides or iodides with BPyCu(CF3)3 (BPy = 2,2'-bipyridine) in aqueous acetone at room temperature to afford the corresponding trifluoromethylation products in good yield. The protocol is applicable to various primary and secondary alkyl halides and exhibits wide functional group compatibility. A mechanism involving trifluoromethyl group transfer from Cu(II)-CF3 intermediates to alkyl radicals is proposed.

Selective Radical Fluorination of Tertiary Alkyl Halides at Room Temperature.

Direct fluorination of tertiary alkyl bromides and iodides with Selectfluor is described. The halogen-exchange fluorination proceeds efficiently in acetonitrile at room temperature under metal-free conditions and exhibits a wide range of functional group compatibility. Furthermore, the reactions are highly selective in that alkyl chlorides and primary and secondary alkyl bromides remain intact. A radical mechanism is proposed for this selective fluorination.

Silver-catalyzed radical fluorination of alkylboronates in aqueous solution.

We report herein an efficient and general method for the deboronofluorination of alkylboronates. Thus, with the catalysis of AgNO3, the reactions of various alkylboronic acids or their pinacol esters with Selectfluor reagent in acidic aqueous solution afforded the corresponding alkyl fluorides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific fluorination.

Efficient, Color-Stable, and Long-Lived White Organic Light-Emitting Diodes Utilizing Phosphorescent Molecular Aggregates.

Highly efficient and stable single-stack hybrid white organic light-emitting diode (WOLED) devices are developed using two emissive layers: one with amber-colored phosphorescent molecular-aggregate emission from the Pd(II) complex, Pd(II) 7-(3-(pyridine-2-yl-κN)phenoxy-κC)(benzo-κC)([c]benzo[4,5]imidazo-κN)[1,2-a][1,5]naphthyridine, Pd3O8-Py5, and the other with blue fluorescence emission. An optimized device structure achieves high color stability under various current densities, an external quantum efficiency (EQE) of 45.5%, a power efficiency of 97.4 Lm W-1 , and an estimated LT95 (operational time to 95% of the initial luminance) of 50 744 h at an initial luminance of 1000 cd m-2 .

Silver-Catalyzed Decarboxylative Bromination of Aliphatic Carboxylic Acids.

The silver-catalyzed Hunsdiecker bromination of aliphatic carboxylic acids is described. With Ag(Phen)2OTf as the catalyst and dibromoisocyanuric acid as the brominating agent, various aliphatic carboxylic acids underwent decarboxylative bromination to provide the corresponding alkyl bromides under mild conditions. This method not only is efficient and general but also enjoys wide functional group compatibility. An oxidative radical mechanism involving Ag(II) intermediates is proposed.