Reducing the load: A facile palladium-catalyzed ortho-selective bromination and chlorination of anilides occurs under aerobic conditions at room temperature when N-halosuccinimides (NXS) are used in presence p-toluenesulfonic acid (PTSA). The orthopalladated PTSA complex is not only catalytically competent but also undergoes a reductive process to yield an unusual PdI–PdII tetramer (see structure; Pd green, O red, S yellow, C gray). Detailed facts importance specialist readers published as...

Although β-diketiminate complexes have been widely explored in stoichiometric studies, their use as catalysts is largely underdeveloped. With growing interest the catalytic activity of first row transition metals, primarily due to untapped potential such metal centers, along with global focus on sustainable chemistry earth abundant this Perspective focuses metals for synthesis small organic molecules.

An iron catalyst has been developed for the transfer hydrogenation of carbon–carbon multiple bonds. Using a well-defined β-diketiminate iron(II) precatalyst, sacrificial amine and borane, even simple, unactivated alkenes such as 1-hexene undergo within 1 h at room temperature. Tuning reagent stoichiometry allows semi- complete terminal alkynes. It is also possible to hydrogenate aminoalkenes aminoalkynes without poisoning through competitive ligation. Furthermore, by exploiting separate...

Iron-catalyzed hydroboration (HB) of alkenes and alkynes is reported. A simple change in ligand structure leads to an extensive catalyst activity. Reactions proceed efficiently over a wide range challenging substrates including activated, unactivated sterically encumbered motifs. Conditions are mild do not require the use reducing agents or other additives. Large excesses borating reagent required, allowing control chemo- regioselectivity presence multiple double bonds. Mechanistic insight...

ADVERTISEMENT RETURN TO ISSUEEditorialNEXTAdvances and Applications in Catalysis with Earth-Abundant MetalsKatherine M. P. Wheelhouse*Katherine WheelhouseDrug Substance Development, GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K.Department of Chemistry, University Bath, Claverton Down, Bath BA2 7AY U.K.Chemical Process Bristol Myers Squibb, One Squibb Drive, New Brunswick, Jersey 08903, United States*Email for K.W.: [email protected]More by Katherine...

ADVERTISEMENT RETURN TO ISSUEEditor's PageNEXTAdvances and Applications in Catalysis with Earth-Abundant MetalsKatherine M. P. Wheelhouse*Katherine WheelhouseDrug Substance Development, GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K.Department of Chemistry, University Bath, Claverton Down, Bath BA2 7AY, U.K.Chemical Process Bristol Myers Squibb, One Squibb Drive, New Brunswick, Jersey 08903, United States*Email for K.W.: [email protected]More by...

The carbamate (–O2CNR2) function is an excellent directing group for palladium-catalysed direct arylation reactions giving both protected or free mono- di-substituted phenols, as well example of a dibenzopyranone, depending on coupling partners (aryl iodides diaryliodonium salts) and conditions.

Solvent-free reaction conditions facilitate a range of aromatic C–H functionalisations that traditionally require acidic or disfavoured solvents. These reactions include selective ortho- and meta-arylation aryl carbamates anilides halogenation reactions.

Eine einfache Pd-katalysierte ortho-selektive Bromierung und Chlorierung von Aniliden gelingt unter aeroben Bedingungen bei Raumtemperatur, wenn N-Halogensuccinimide (NXS) in Gegenwart p-Toluolsulfonsäure (PTSA) eingesetzt werden. Der orthopalladierte PTSA-Komplex ist nicht nur katalytisch aktiv, sondern geht auch einen reduktiven Prozess Bildung eines ungewöhnlichen PdI-PdII-Tetramers ein (siehe Struktur; Pd grün, O rot, S gelb, C grau). Detailed facts of importance to specialist readers...

A highly active iron(<sc>iii</sc>) complex for room temperature hydrophosphination is reported. The products of the reaction are also useful ligands iron catalyzed Negishi cross-coupling.

A series of pyridonate and amidate supported titanium alkoxides have been isolated. These complexes can be readily prepared in high yield, under mild reaction conditions only two steps from commercially available (Ti(NMe(2))(4)). We furnished one the rare examples discrete catalysts for random copolymer synthesis.

The catalytic addition of phosphines to alkenes and alkynes is a very attractive process that offers access in 100% atom-economic reaction using readily available inexpensive materials. products are potentially useful ligands organocatalysts. Herein, we report the first example intramolecular hydrophosphination series nonactivated phosphinoalkenes phosphinoalkynes with simple iron β-diketiminate complex. Kinetic studies suggest this transformation first-order respect both phosphine catalyst....

Dehydrocoupling of phosphine- and amine-boranes is reported using an iron(II) β-diketiminate complex. far more facile than the phosphine counterpart, former proceeding at room temperature with 1 mol% iron precatalyst. This low loading sufficient to allow in situ kinetic analysis deuterium labeling studies be carried out. An amido-borane complex has also been isolated, which believed catalyst resting state. Overall, this allowed us postulate a catalytic cycle proceeds via release diborazane,...

Catalytic dehydrocoupling of primary and secondary phosphines has been achieved for the first time using an iron pre-catalyst. The reaction proceeds under mild conditions is successful with a range diarylphosphines. A proton acceptor not needed transformation to take place, but addition 1-hexene does allow turnover at 50 °C. catalytic system developed also facilitates phenylphosphane dicyclohexylphosphane. change in solvent switches off hydrophosphination alkenes.

Abstract Palladium(II) acetate is readily converted into [Pd 3 (μ 2 ‐OH)(OAc) 5 ] ( 1 ) in the presence of water a range organic solvents and also slowly solid state. Complex can be formed nominally anhydrous solvents. Similarly, analogous alkoxide complexes ‐OR)(OAc) are easily solutions palladium(II) containing alcohols. An examination representative Wacker‐type oxidation shows that Pd‐OH complex related Pd‐oxo 4 excluded as potential catalytic intermediates absence exogenous water.

A detailed synthetic investigation into the dehydrocoupling of silanes with amines, phosphines, and alcohols using an iron precatalyst (1) is presented. We have furnished over 30 examples aminosilane synthesis along kinetic studies MeBnNH MePhSiH2 as coupling partners. The suggest a reversible reaction silane which generates Fe-hydride dimer that undergoes rate-limiting protonolysis amine N–H bond cleavage in transition state, consistent primary KIE 2.42(3). presence dimers on-cycle...

The solvent-free, palladium-catalysed reaction of anilides with CuCl(2) in the presence or absence copper acetate yields ortho-chlorinated good to excellent yields, even on a large scale (100 mmol). By contrast, equivalent reactions bromide, either solvent free 1,2-dichloroethane, palladium, under air inert conditions, gave products simple electrophilic bromination. Mechanistic studies highlighted involvement palladacyclic intermediates, one which was characterised crystallographically,...

The rhodium-catalysed direct ortho-arylation of protected racemic 2-tert-butyl tyrosine has been developed. subsequent removal the tert-butyl group yields 2-arylated which can undergo further rhodium-based arylation at 6-position. In one instance a product formed by diarylated species was isolated.

A series of titanium pyridonate complexes have been synthesized under very mild reaction conditions from a common precursor, Ti(NMe₂)₄. These explored as initiators for the ring-opening polymerization <italic>rac</italic>-lactide and ε-caprolactone proven to be competitive with leading initiators.

Abstract The importance of phosphines in synthetic chemistry cannot be underestimated. Catalytic hydrophosphination offers an ideal method to prepare P−C bonds without the need for harsh reaction conditions or stoichiometric amounts waste by‐product. We herein report our studies into two biocompatible iron(III) complexes using diphenylphosphine under mild and benign (room temperature, solvent‐free) extended exploration with phenylphosphine, which can tuned operate absence catalyst thermal...

The ability to tune between different regioselectivities using a common pre-catalyst is an unusual yet highly desirable process. Here, we report the use of iron(II) that can be used synthesize vinyl phosphines in Markovnikov-selective manner benzene, whereas simple change dichloromethane as reaction solvent leads Z-selective anti-Markovnikov product. Preliminary mechanistic studies are reported suggest Markovnikov selectivity radical-mediated process, not radical nature but due oxidation state.

A homologous series of 1,1-diphosphines have been prepared by alkyne hydrophosphination using catalytic KHMDS at room temperature.

A mild, efficient, and regiospecific catalytic cyclotrimerization of alkynes to form 1,2,4-substituted arenes has been discovered. From a cheap air-stable [Fe(salen)]2-μ-oxo complex readily available pinacol borane (HBpin), monomeric [FeH(salen)]·Bpin species formed in situ acts as the active catalyst. This is shown feature hemilabile salen ligand stabilized via interactions with boron entity. The formation, identity, reaction mechanism are supported by complementary kinetic, spectroscopic,...