The Heck reaction was found to proceed markedly more efficiently in the ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim][Br]) than analogous tetrafluoroborate salt ([bmim][BF4]). In relation this observation, 1-butyl-3-methylimidazol-2-ylidene (bmiy) complexes of palladium [PdBr(μ-Br)(bmiy)]2 (1) and [PdBr2(bmiy)2] (2) have been isolated [bmim][Br] but not [bmim][BF4] under conditions similar those employed for reaction. both molecular solvents, complex 2 formed via intermediate 1....

Two versatile strategies for preparing metal–organic conjugated microporous polymers (MO-CMPs) containing metals such as rhenium, rhodium, and iridium are described (see example). These materials combine the uninterrupted extended electronic conjugation in network with catalytically active metal sites.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTMetal−Brønsted Acid Cooperative Catalysis for Asymmetric Reductive AminationChaoqun Li, Barbara Villa-Marcos, and Jianliang Xiao*View Author Information Liverpool Centre Materials Catalysis, Department of Chemistry, University Liverpool, L69 7ZD, U.K.[email protected]Cite this: J. Am. Chem. Soc. 2009, 131, 20, 6967–6969Publication Date (Web):April 29, 2009Publication History Received19 March 2009Published online29 April inissue 27 May...

In buffered water, a broad range of quinoline derivatives underwent asymmetric transfer hydrogenation in air with the rhodium catalyst 1 and sodium formate as hydrogen source to furnish synthetically important 1,2,3,4-tetrahydroquinolines excellent enantioselectivities (see scheme; R=H, Me, F, Cl, Br, OMe; R′=alkyl, aryl). Detailed facts importance specialist readers are published "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available...

Gas up: A cyclometalated iridium complex is found to catalyze the dehydrogenation of various benzofused N-heterocycles, thus releasing H2. Driven by as low 0.1 mol % catalyst, reaction affords quinolines, indoles, quinoxalines, isoquinolines, and β-carbolines in high yields. As a service our authors readers, this journal provides supporting information supplied authors. Such materials are peer reviewed may be re-organized for online delivery, but not copy-edited or typeset. Technical support...

Chemical recycling is one of the most promising technologies that could contribute to circular economy targets by providing solutions plastic waste; however, it still at an early stage development. In this work, we describe first light-driven, acid-catalyzed protocol for chemical polystyrene waste valuable chemicals under 1 bar O2. Requiring no photosensitizers and only mild reaction conditions, operationally simple has also been demonstrated in a flow system. Electron paramagnetic resonance...

A mild and operationally simple iron-catalyzed protocol for the selective aerobic oxidation of aromatic olefins to carbonyl compounds is described. Catalyzed by a Fe(III) species bearing pyridine bisimidazoline ligand at 1 atm O2, α- β-substituted styrenes were cleaved afford benzaldehydes ketones generally in high yields with excellent chemoselectivity very good functional group tolerance, including those containing radical-sensitive groups. With α-halo-substituted styrenes, took place...

Heteroatom-participated lignin depolymerization for heterocyclic aromatic compounds production is of great importance to expanding the product portfolio and meeting value-added biorefinery demand, but it also particularly challenging. In this work, synthesis pyrimidines from β-O-4 model compounds, most abundant segment in lignin, mediated by NaOH through a one-pot multi-component cascade reaction reported. Mechanism study suggests that transformation starts NaOH-induced deprotonation Cα-H...

When combined with a chiral phosphate counteranion, diamine-ligated Ir(III) catalyst displayed excellent enantioselectivities in the asymmetric hydrogenation of wide range acyclic imines, affording amines up to 99% ee.

Palladium-catalyzed regioselective Heck arylation of the electron-rich olefins, vinyl ethers 1a-d, enamides 1e-g, and allyltrimethylsilane 1h, has been accomplished in imidazolium ionic liquids with a wide range aryl bromides iodides instead commonly used, but commercially unavailable expensive, triflates. The reaction proceeded high efficiency remarkable regioselectivity without need for costly or toxic halide scavengers, leading exclusively to substitution by groups diverse electronic...

An iridium catalyst enables the reductive amination of carbonyl groups with unprecedented substrate scope, selectivity, and activity using formic acid as hydrogen source (see scheme). The system provides significant improvement over commonly used boron hydrides. Detailed facts importance to specialist readers are published "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by authors. Please note: publisher is responsible for...

In gepuffertem Wasser wurde ein breites Spektrum von Chinolinen durch asymmetrische Transferhydrierung an der Luft mit dem Rhodiumkatalysator 1 und Natriumformiat als Wasserstoffquelle ausgezeichneten Enantioselektivitäten zu den präparativ nützlichen 1,2,3,4-Tetrahydrochinolinen umgesetzt (siehe Schema; R=H, Me, F, Cl, Br, OMe; R′=Alkyl, Aryl).

Asymmetric transfer hydrogenation (ATH) of ketones by formate in neat water is shown to be viable with Rh-TsDPEN and Ir-TsDPEN catalysts, derived situ from [Cp*MCl2]2 (M=Rh, Ir) TsDPEN. A variety were reduced, including nonfunctionalized aryl ketones, heteroaryl ketoesters, unsaturated ketones. In comparison the related Ru II catalyst, Rh III catalyst most efficient water, affording enantioselectivities up 99 % ee at substrate/catalyst (S/C) ratios 100-1000 even without working under an...

Much faster, more enantioselective, and more-productive catalysis was attained in the asymmetric transfer hydrogenation of aromatic ketones with Noyori–Ikariya Ru–Ts-dpen catalyst water under slightly basic conditions (see scheme). At low pH values, reaction much less efficient appears to operate through a different mechanism.

Asymmetric transfer hydrogenation of various simple aromatic ketones by the Ru-TsDPEN catalyst was shown to be feasible in aqueous HCOONa without calling for any modification, furnishing ee's up 95% and significantly faster rates than HCOOH–NEt3 azeotrope.

When associated with a noncoordinating bulky counteranion, cationic Cp*Rh(III)-diamine catalyst displayed excellent enantioselectivities in asymmetric hydrogenation of cyclic imines, affording bioactive tetrahydroisoquinolines and tetrahydro-β-carbolines frequently 99% ee's.

The mechanism of aqueous-phase asymmetric transfer hydrogenation (ATH) acetophenone (acp) with HCOONa catalyzed by Ru-TsDPEN has been investigated stoichiometric reactions, NMR probing, kinetic and isotope effect measurements, DFT modeling, X-ray structure analysis. chloride [RuCl(TsDPEN)(p-cymene)] (1), hydride [RuH(TsDPEN)(p-cymene)] (3), the 16-electorn species [Ru(TsDPEN-H)(p-cymene)] (4) were shown to be involved in aqueous ATH, 1 being precatalyst, 3 as active catalyst detectable both...

Rose Bengal dye has been successfully integrated into the skeleton of a conjugated microporous polymer via palladium-catalyzed Sonogashira–Hagihara cross-coupling polycondensation. These polymers are stable in various solvents, including concentrated hydrochloric acid, and thermally stable. The resulting show substantial porosity highly active for heterogeneous photocatalytic aza-Henry reactions at room temperature wide range substrates. Moreover, this noble-metal-free photocatalyst shows...

[reaction: see text] The poly(ethylene glycol)-supported ruthenium precatalyst shown above is highly effective for asymmetric transfer hydrogenation of unfunctionalized aromatic ketones by HCOONa in neat water, affording fast rates, good to excellent enantioselectivities, and outstanding reusability.

Wasser als Lösungsmittel: Schnell, selektiv und in hoher Ausbeute gelingt die Transferhydrierung einer großen Bandbreite an Aldehyden mit einem IrIII-Katalysator, der einfache Ethylendiamin(en)-Liganden enthält (siehe Schema; Ts=p-Toluolsulfonyl, TOF=Reaktionsrate). Das Verfahren eignet sich für sehr unterschiedlich substituierte Aldehyde.