The use of readily available chiral trans-cyclohexanediamine-benzimidazole derivatives as bifunctional organocatalysts in the asymmetric electrophilic amination of unprotected 3-substituted oxindoles is presented. Different organocatalysts were evaluated; the most successful one contained a dimethylamino moiety (5). With this catalyst under optimized conditions, different oxindoles containing a wide variety of substituents at the 3-position were aminated in good yields and with good to excellent enantioselectivities using di-tert-butylazodicarboxylate as the aminating agent. The procedure proved to be also efficient for the amination of 3-substituted benzofuranones, although with moderate results. A bifunctional role of the catalyst, acting as Brønsted base and hydrogen bond donor, is proposed according to the experimental results observed.

In order to prepare new phosphorescent iridium(III) emitters, 2-phenyl-6-(1phenyl-1-(pyridin-2-yl)ethyl)pyridine (H2L) has been designed and its reactions with [Ir(μ-Cl)(η 4 -COD)]2 (1, COD = 1,5-cyclooctadiene) have been studied. The products obtained depend on the refluxing temperature of the solvent. Thus, complexes Ir(κhave been formed in 2-ethoxyethanol, propan-2-ol, and 1-phenylethanol, respectively. Complex 4 reacts with K(acac) to give the acetylacetonate derivative Ir(κ 4 -C,C',N,N'-L)(acac) (5). Complexes 2 and 5 are efficient blue-green and green emitters of the classes [6tt+1m+2m] and [6tt+3b], respectively. They display lifetimes in the range 1.1-4.5 μs and high quantum yields (0.87-0.54) in both PMMA films and 2-MeTHF at room temperature.spin−orbit coupling and thermally accessible metal-centered d−d states. 10 In addition, emitters with tridentate and tetradentate ligands give rise to less problems of isomers and reactions of redistribution than complexes stabilized by bidentate and monodentate ones, as a consequence of the reduction of the number of ligands attached to the metal for a given coordination index.Tetradentate ligands with planar skeleton have been the most commonly used, 11 while the photophysical properties of Ir(III)-emitters with nonplanar ligands (Chart 1) have received scarce attention. 12 An increase of the phosphorescence efficiency has been attained by tethering the ortho-carboranes attached to the 5-positions of ortho-metalated 2-phenylpyridine ligands (complex A). 13 2,7-Bis(2-(2-(4-(pyridin-2-yl)phenoxy)ethoxy)ethoxy)naphthalene has been employed to prepare cations B, in order to explore its use for white-light emission. 14 Hung, Chou, Chi, and coworkers have prepared 2,2'-(1-(6-pyrazol-5-yl)pyridin-2-yl)ethane-1,1diyl)dipyridine molecules. These precursors afford monoanionic tetradentate ligands (7tt), which stabilize iridium(III) complexes of the classes [7tt+1m+1m] and [7tt+2b] (C and D). Complexes C (R = H, t Bu) showed no perceptible emission. However, the substitution of the monodentate chlorides (1m) by a bipyrazolate ligand (2b), to give D (R = H, t Bu), produces a dramatic increase in the emission efficciency. 15 We have used 1,1-diphenyl-3,3-butylenediimidazolium iodide, to prepare the [6tt+3b] emitters E, which display blue-green emissions with quantum yields close to unity. 16 Lee, Chi, and coworkers have recently replaced a peripheral pyridine in one of the organic molecules (R = H), previously prepared by the Hung-Chou-Chi's group, by a phenyl susceptible to undergo ortho-CH bond activation. The resulting dianionic tetradentate ligand (6tt) stabilizes mononuclear [6tt+1m+2m] (F) and binuclear emitters. The diiridium compounds exhibited bright sky-blue to green emissions. 17

The asymmetric synthesis of 3-substituted oxindoles is at opico fc onsiderable importance because these functionalized heterocycles are found in many natural products and drugs. In the last decade, significant advances have been made towards the asymmetric synthesis of 3-heteroatom-substituted oxindoles as ar esult of major improve-ments in asymmetric organocatalysis. This review will focus on the different types of asymmetric electrophilic organocatalyzed reactions, including the amination, halogenation,h ydroxylation,a nd sulfenylation of oxindoles to form their enantioenriched 3-heterosubstituted derivatives.The ORCID identification number(s) for the author(s) of this articlecan be found under https://doi.

1-Phenyl-3-(1-phenyl-1-(pyridin-2-yl)ethyl)isoquinoline (H 2 MeL) has been prepared by Pd( N -XantPhos)-catalyzed “ deprotonative cross-coupling processes ” to synthesize new phosphorescent red iridium(III) emitters (601–732 nm), including the carbonyl derivative Ir(κ 4 - cis - C , C ′- cis - N , N ′-MeL)Cl(CO) and the acetylacetonate compound Ir(κ 4 - cis - C , C ′- cis - N , N ′-MeL)(acac). The tetradentate 6e-donor ligand (6tt′) of these complexes is formed by two different bidentate units, namely, an orthometalated 2-phenylisoquinoline and an orthometalated 2-benzylpyridine. The link between the bidentate units reduces the number of possible stereoisomers of the structures [6tt′ + 3b] (3b = bidentate 3e-donor ligand), with respect to a [3b + 3b′ + 3b″] emitter containing three free bidentate units, and it permits a noticeable stereocontrol. Thus, the isomers fac -Ir(κ 4 - cis - C , C ′- cis - N , N ′-MeL){κ 2 - C , N -(C 6 H 4 -py)}, mer -Ir(κ 4 - cis - C , C ′- cis - N , N ′-MeL){κ 2 - C , N -(C 6 H 3 R-py)}, and mer -Ir(κ 4 - trans - C , C ′- cis - N , N ′-MeL){κ 2 - C , N -(C 6 HR-py)} (R = H, Me) have also been selectively obtained. The new emitters display short lifetimes (0.7–4.6 μs) and quantum yields in a doped poly(methyl methacrylate) film at 5 wt % and 2-methyltetrahydrofuran at room temperature between 0.08 and 0.58. The acetylacetonate complex Ir(κ 4 - cis - C , C ′- cis - N , N ′-MeL)(acac) has been used as a dopant for a red PhOLED device with an electroluminescence λ max of 672 nm and an external quantum efficiency of 3.4% at 10 mA/cm 2 .