The ability of Lewis acids to coordinate transition metals as σ-acceptor ligands was recognized early in the 1970's, but so-called Z-type remained curiosities until 2000's. Over last decade, significant progress has been made this area, especially via incorporation acid moieties into multidentate, ambiphilic ligands. Our understanding nature and influence TM → Z interactions considerably improved scope susceptible behave significantly extended. This feature article summarizes these recent...

The reluctance of gold to achieve oxidative addition reaction is considered as an intrinsic limitation for the development gold-catalyzed cross-coupling reactions with simple and ubiquitous aryl halide electrophiles. Here, we report rational construction a Au(I)/Au(III) catalytic cycle involving sequence Csp2-X addition, Csp2-H auration reductive elimination, allowing direct arylation arenes halides. Key this discovery use Me-Dalphos, ancillary (P,N) ligand, that allows bottleneck iodides...

Singlet diradicals are usually not energy minima. As observed by femtosecond spectroscopy, they readily couple to form final sigma bonds. Substituent effects allow lifetimes increase into the microsecond range. Taking advantage of properties hetero-elements, a diradical has been prepared that is indefinitely stable at room temperature. The availability can be handled under standard laboratory conditions will lead further insight their chemical and physical properties, raising likelihood...

The phosphonium borane [1-Mes2B-2-MePh2P-(C6H4)]+ ([2]+) has been synthesized as an iodide salt by alkylation of 1-Mes2B-2-Ph2P-(C6H4) with MeI. This novel cationic complexes fluoride to afford the corresponding zwitterionic fluoroborate complex 1-FMes2B-2-MePh2P-(C6H4) (2-F) a binding constant in MeOH exceeding that 1-Mes2B-4-MePh2P-(C6H4) ([1]+) at least 4 orders magnitude. Structural and computational results indicate high fluorophilicity [2]+ arises from both Coulombic cooperative...

Dual systems combining Zn(C6F5)2 with an organic base (an amine or a phosphine) promote the controlled ring-opening polymerization of lactide and ε-caprolactone. The Lewis pairs cooperate to activate monomers, affording well-defined high molecular weight cyclic polyesters. Efficient chain-extension gives access block copolymers.

Symmetry from within: Coordination of a triphosphanyl–borane ligand to gold(I) and platinum(0) affords metallaboratranes exhibiting C3 symmetry both in solution the solid state. Such helical geometry is supported by axial M→B dative interactions results envelope conformations PCCBM metallacycles. Supporting information for this article available on WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z705024_s.pdf or author. Please note: The publisher not responsible content functionality...

Coordination of an ambiphilic diphosphine-borane (DPB) ligand to the RhCl(CO) fragment affords two isomeric complexes. According X-ray diffraction analysis, each complex adopts a square-pyramidal geometry with trans coordination phosphine buttresses and axial RhB contacts, but differ in relative orientations around rhodium boron centres. DFT calculations on actual complexes provide insight into influence pi-accepting CO co-ligand, compared previously reported [Rh(mu-Cl)(dpb)]2...

Taking advantage of phosphine chelation, direct evidence for oxidative addition Csp2–X bonds (X = I, Br) to a single gold atom is reported. NMR studies and DFT calculations provide insight into this unprecedented transformation, which gives straightforward access stable (P,C) cyclometalated gold(III) complexes.

Reaction of the geminal PAl ligand [Mes2PC(═CHPh)AltBu2] (1) with [Pt(PPh3)2(ethylene)] affords T-shape Pt complex [(1)Pt(PPh3)] (2). X-ray diffraction analysis and DFT calculations reveal presence a significant Pt→Al interaction in 2, despite strain associated four-membered cyclic structure. The Pt···Al distance is short [2.561(1) Å], Al center pyramidal environment [Σ(C-Al-C) = 346.6°], PCAl framework strongly bent (98.3°). Release ring formation X→Al interactions (X O, S, H) impart rich...

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTOrgano-Catalyzed ROP of ϵ-Caprolactone: Methanesulfonic Acid Competes with Trifluoromethanesulfonic AcidStéphanie Gazeau-Bureau†, Damien Delcroix†, Blanca Martín-Vaca*†, Didier Bourissou*†, Christophe Navarro‡, and Stéphanie Magnet‡View Author Information Laboratoire Hétérochimie Fondamentale et Appliquée du CNRS (UMR 5069), Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse Cedex 09, France,...

The oxidative addition of strained CC bonds (biphenylene, benzocyclobutenone) to DPCb (diphosphino-carborane) gold(I) complexes is reported. resulting cationic organogold(III) have been isolated and fully characterized. Experimental conditions can be adjusted obtain selectively acyl gold(III) from either the C(aryl)C(O) or C(alkyl)C(O) bond benzocyclobutenone. DFT calculations provide mechanistic insight into this unprecedented transformation.

The ability of the hemilabile (P,N) MeDalphos ligand to trigger oxidative addition iodoarenes gold has been thoroughly studied. Competition experiments and Hammett correlations substantiate a clear preference for electron-enriched substrates both in stoichiometric reactions catalytic C-C cross-coupling with 1,3,5-trimethoxybenzene. This feature markedly contrasts higher reactivity electron-deprived typically encountered palladium. Based on DFT calculations detailed analysis key transition...

Abstract Heteroarylation of alkenes with aryl iodides was efficiently achieved a (MeDalphos)AuCl complex through Au I /Au III catalysis. The possibility to combine oxidative addition and π‐activation at gold is demonstrated for the first time. reaction robust general (>30 examples including internal alkenes, 5‐, 6‐, 7‐membered rings). It regioselective leads exclusively trans products. (P,N) most efficient electron‐rich substrates, which are troublesome alternative photoredox/oxidative...

Ambiphilic phosphine–borane derivatives 1-B(OR)2-2-PR′2–C6H4 (R′ = Ph (1), iPr (2); (OR)2 (OMe)2 (1a, 2a); catechol (1b, 2b) pinacol (1c, 2c), −OCH2C(CH3)2CH2O– (1d)) were tested as catalysts for the hydroboration of CO2 using HBcat or BH3·SMe2 to generate methoxyboranes. It was shown that most active species 1b and 2b. In presence HBcat, without CO2, ambiphilic 1a, 1c, 1d transform 1b, whereas 2a 2c The formaldehyde adducts 1b·CH2O 2b·CH2O are postulated be in reduction rather than being...

The capture and utilization of CO2 to prepare high-value compounds is very attractive chemically highly desirable socially. Indenediide-based Pd SCS pincer complexes are shown here promote the carboxylative cyclization propargylamines leading 2-oxazolidinones under mild conditions (0.5–1 bar CO2, DMSO, 40–80 °C, 1–5 mol % loading). indenediide complex competitive with known catalysts. It proved successful for a wide range propargylamines, including hitherto challenging substrates such as...

The specific electronic properties of bent o-carborane diphosphine gold(I) fragments were exploited to obtain the first classical carbonyl complex gold [(DPCb)AuCO](+) (ν(CO)=2143 cm(-1) ) and diphenylcarbene [(DPCb)Au(CPh2 )](+) , which is stabilized by fragment rather than carbene substituents. These two complexes characterized spectroscopic crystallographic means. [(DPCb)Au](+) plays a major role in their stability, as substantiated DFT calculations. bending induced ligand substantially...

Gold-catalyzed coupling of aryl iodides and amines <italic>via</italic> a ligand-enabled 2e redox cycle.

Abstract Borenium cations have been found to be valuable analogues of boranes as a result their cationic character which imparts high electrophilicity. Herein, we report the synthesis, characterization, and reactivity new type borenium cation employing naphthyl bridge strong intramolecular P→B interaction. The reacts with H 2 in presence P t Bu 3 (frustrated Lewis pair (FLP) approach) but also on its own. mechanism reaction between absence has investigated using deuterium‐labeling...