A highly efficient and enantioselective hydrogenation of unprotected β-enamine esters catalyzed by Ir-(S,S)-f-Binaphane complex has been developed. This methodology provides straightforward access to free β-amino acids in high yields with excellent enantioselectivities up to 97% ee and high reactivities (TON > 5000).

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With the aim of evaluating the potential of selenium-containing groups in developing electroluminescent (EL) materials, a series of asymmetric heteroleptic Ir(III) phosphorescent complexes (Ir-Se0F, Ir-Se1F, Ir-Se2F, and Ir-Se3F) have been synthesized by using 2-selenophenylpyridine and one ppy-type (ppy = 2-phenylpyridine) ligand with a fluorinated selenide group. To the best of our knowledge, these complexes represent unprecedented examples of asymmetric heteroleptic Ir(III) phosphorescent emitters bearing selenium-containing groups. Natural transition orbital (NTO) analysis based on optimized geometries of the first triplet state (T) have shown that the phosphorescent emissions of these Ir(III) complexes dominantly show π-π* features of the 2-selenophenylpyridine ligand with slight metal to ligand charge transfer (MLCT) contribution. In comparison with their symmetric parent complex Ir-Se with two 2-selenophenylpyridine ligands, these asymmetric heteroleptic Ir(III) phosphorescent complexes can show much higher phosphorescent quantum yields (Φ) of ca. 0.90. Both the hole- and electron-trapping ability of these Ir(III) phosphorescent complexes can be enhanced by selenophene and fluorinated selenide groups to improve their EL efficiencies. The EL abilities of these asymmetric heteroleptic Ir(III) phosphorescent emitters fall in the order Ir-Se3F > Ir-Se2F > Ir-Se1F > Ir-Se0F. The highest EL efficiencies have been achieved by Ir-Se3F in the solution-processed OLEDs with external quantum efficiency (η), current efficiency (η), and power efficiency (η) of 19.9%, 65.6 cd A, and 57.3 lm W, respectively. These encouraging EL results clearly indicate the great potential of selenium-containing groups in developing high-performance Ir(III) phosphorescent emitters.

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Asymmetric hydrogenation of a-dehydroamino ketones catalyzed by a rhodium-chiral phosphorus ligand complex (up to 99% ee, 1000 TON), represents an efficient approach to chiral aamino ketones. The reduction of a-amino ketones catalyzed by palladium on carbon (Pd/C) leads to amphetamine precursors with quantitative yield and no significant enantioselectivity loss.

Enantiomerically pure b-amino nitriles and their derivatives are important intermediates in organic synthesis and pharmaceutical chemistry. The nitrile group is one of the most versatile functional groups in organic chemistry and can be readily transformed into a variety of valuable functionalities, [1] including carboxyl; aldehyde; and amino groups, and, hence, b-amino nitriles enable facile approaches to b-amino acids, aldehydes, and 1,3-diamines. Therefore, the synthesis of b-amino nitriles has attracted much attention in recent decades. The early preparation of b-amino nitriles started from b-amino alcohols and involves a reaction with toxic cyanic reagents.[2] Some recent progress [3] includes addition reactions of alkyl nitriles to imines catalyzed by Cu, [4] Pd, [5] Ru, [6] or Lewis base [7] complexes, with good yields. An alternative approach to b-amino nitriles is the ring-opening of aziridines with trimethylsilyl cyanide (TMSCN). [8] To the best of our knowledge, there are few reports of the direct preparation of chiral b-amino nitriles by asymmetric hydrogenation of the corresponding b-amino acrylonitriles. [9] This is mainly due to the electronic structure of nitriles, which prefer the end-on coordination of metal ions, making the conjugated double bond unsuitable for hydrogenation reactions. Another challenge in the direct hydrogenation of b-amino acrylonitriles is achieving chemoselectivity between the olefinic double bond and the nitrile group. [10] Asymmetric hydrogenation catalyzed by transition metals has proved to be a highly efficient method for the synthesis of chiral amines. A number of chiral phosphine ligands have been developed that improve the chemo-and enantioselectivity of the hydrogenation reaction.[11] We envisioned that the electron-donating, rigid, chiral ligands, such as TangPhos, DuanPhos, and Binapine (shown here), developed in our research group, [11d] could be efficient ligands for the hydrogenation of b-amino acrylonitriles. Herein, we report the first direct asymmetric hydrogenation of b-amino acrylonitriles with a Rh-TangPhos catalyst, providing the corresponding b-amino nitriles in excellent enantioselectivities (up to 99.4 % ee) and tolerating E/Z mixtures of substrate.[11a]b-Amino acrylonitriles can be readily prepared in two steps with good yield (Scheme 1). [12] With (E)-3-acetylamino-3-phenylacrylonitrile [(E)-1 a)] as a model substrate, we screened several electron-donating ligands developed in our group, and some commercially available chiral ligands, such[a] M.

A series of (C^N)Pt(acac)-type complexes have been successfully synthesized with benzo[b]furan, benzo[b]thiophene, benzo[b]selenophene and benzo[b]tellurophene groups in their benzoayrl-pyridine ligands, respectively. With X-ray crystallography, the chemical structures for the complexes...

The Grubbs-Hoveyda ruthenium-carbene complex has been covalently immobilized on ionic magnetic nanoparticles utilizing an imidazolium salt linker. The supported catalyst exhibited excellent catalytic activity for ring-closing metathesis (RCM) and cross-metathesis (CM) in the presence of less than 1 mol % of ruthenium. The catalysts can easily be recovered magnetically and reused up to seven times with minimal leaching of ruthenium species.