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Using the dihydroxylation of alkenes as a benchmark, the reactivities of fresh and aged solutions of (NH4)2S2O8 (electrochemically generated) were compared to commercially-procured peroxydisulfate and Oxone®. The study revealed that peroxymonosulfate (Caro’s acid, PMS) is the active oxidant in such reactions. Using complementary redox colorimetry and in situ IR spectroscopy to monitor the oxidants, the competitive decomposition of peroxydisulfate in an acidic solution into PMS and H2O2 can be quantified for the first time. The new insight enabled the design and implementation of both batch and flow processes to maximise the concentration of active PMS oxidant. The utility of these oxidants for organic synthesis is demonstrated by the dihydroxylation of eight styrenes and seven alkyl alkenes, where the ammonium PMS solutions performed better than Oxone® (counterion effect). Last but not least, a non-chromatographic method for isolating and purifying the water-soluble diol product was developed.

The reduction of γ-Al2O3-supported PdO in flowing aqueous ethanol was investigated. Quick EXAFS (QEXAFS) performed at the Pd K-edge reveals that the presence of Cl can have a profound effect on the reduction process. At low loadings of Pd (1 wt-%), the size dependency of the process is inverted, compared to Cl-free samples. The extent of reduction was found to be dependent on loading/particles size. It is shown, using in situ QEXAFS at the Cl K- and Pd L3-edges, that residual Cl is not removed by the flowing solvent mixture, even at an elevated temperature of 350 K. The origins of these behaviours are discussed in terms of the differing effects that Cl may have when bonded to oxidic or reduced metal centres and the results were compared to earlier observations made on the effects of Cl on commercial polyurea encapsulated Pd ENCAT™ NP 30 catalysts.

International audience; Ethanol-water, a prototypical 'green' solvent mixture, cannot be considered as inert toward supported Pd nanoparticles. We establish severe size dependencies in Pd redox behavior, persistent gradients in Pd phase in a plug-flow situation, and that Pd nanoparticles are contaminated with hydrogen derived from the solvent

Transmission electron microscopy (TEM) is commonly used as an ex-situ technique to determine structural changes by comparing images of catalyst particles before and after a reaction. This requires the use of an alcoholic solvent to disperse the particles on a grid. In this work, we will show that Pd catalysts can be transformed during the procedure, by using EXAFS to determine the structure of Pd catalysts in different environments (as dry or wet samples). Supported palladium nanoparticles exposed to aqueous ethanolic solution (50% w/v) are transformed to a common, reduced, and hydrogen-contaminated state, irrespective of their initial habit or support. Catalysts comprised of nanosize PdO are reduced at ca. 350 K, whereas samples comprised of very small (ca. ≤ 10 atoms) Pd particles react with the solvent at just above room temperature and agglomerating with considerable loss of dispersion. As such any potential benefits to catalysis sought through the synthesis of very highly dispersed metallic Pd supported upon a range of inorganic dispersants will be rapidly erased through the action of such solvents.

Herein we report a Suzuki-Miyaura type cross-coupling between an aryl halide and a functionalized boronic acid palladacycle in the absence of an external catalyst. This reaction is an unprecedented case of catalysis in palladium metallacycle chemistry.

The nuclearity and structures of the palladium complex [(SPhos)Pd(Ph)Cl]

The nuclearity and structures of the palladium complex [(SPhos)Pd(Ph)Cl]2 in the solid and solution states are revisited using a combination of Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, NMR spectroscopy, mass spectrometry, DFT calculations and trapping experiments. The complex was tested for its catalytic activity in the coupling reaction between chlorobenzene and n-hexylamine, where different deactivation behaviours were observed in toluene, 1,4-dioxane and DMF.

Bimetallic cyclometallated palladium(II) complexes readily react with silver perchlorate and tertiary diphosphines to give dipalladium compounds with terdentate [C,N,S] thiosemicarbazones, and with bridging and chelating [P,P] ligands, of the type [Pd(Ph2PCH2PPh2-P,P){Pd[4-MeOC6H3C(Me)NNC(S)NHMe](Ph2PCH2PPh2)-P,S}] [ClO4]2, 1a. The crystal structures of complexes [PdCl2{Pd[2-MeOC6H3C(Me)NNC(S)NHMe](Ph2PC(CH2)2PPh2)-P,S}] and [Pd(Ph2PCH2PPh2-P,P){Pd[3-MeOC6H3C(Me)NNC(S)NHMe](Ph2PC(CH2)2P-Ph2)-P,S}]-[ClO4]2, 6 and 4a, respectively, are the first reported examples of palladacycles with the diphosphine Ph2PC(CH2)2PPh2, bis(diphenylphosphine)cyclopropane (dcpc), in the bridging mode. The short-bite diphosphines produce strained four-membered rings at the metal; the structures for 1a and 4a show the P–C–P carbon atom puckered away from the metal coordination plane.

The direct addition of O-H bonds to C=C bonds is a very attractive way of synthesising alcohols, ethers and esters, due to the inherent atom- and step-economy of the process. This microreview focuses on the development of group 11 metal catalysts in mediating these transformations. Bronsted acid catalysis has been shown to play a role in some of these processes, and this is highlighted where appropriate. The utility of these methods in organic synthesis is addressed through selected examples. The direct addition of O-H bonds to C=C bonds is an attractive way to synthesise alcohols, ethers and esters. This microreview addresses the use of group 11 metals in promoting these transformations. The involvement of Bronsted acid catalysis in some of these reactions is highlighted. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The ability of silver complexes to catalyse the enantioselective addition of O-H and N-H bonds to allenes is demonstrated for the first time by using optically active anionic ligands that were derived from oxophosphorus(V) acids as the sources of chirality. The intramolecular addition of acids, alcohols, and amines to allenes can be achieved with up to 73% ee. The exploitation of a C-H anomeric effect allowed the absolute configuration of a sample of 2-substituted tetrahydrofuran of low ee to be unambiguously assigned by comparison of the chiroptical ORD and VCD measurements with calculated spectra. In the second part of the work, the origin of the stereoselectivity was probed by DFT free-energy calculations of the transition states. A new model of enantiomeric differentiation was developed that was based on noncovalent interactions. This model allowed us to identify the source of stereoselectivity as weak attractive interactions; such dispersive forces are often overlooked in asymmetric catalysis. A new computational approach was developed that represents these interactions as colour-coded isosurfaces that are characterised by the reduced density-gradient profile.

The preparation of two new chiral, enantiopure, and conformationally constrained phosphocin and 1,5-diphosphocin, incorporating two ferrocenyl units, is described. The gold(I) chloride complexes of these ligands and (S)-(R)-PPF-OMe were prepared, and their structures, in solution and solid states, are compared. Abstraction of the chloride anion by the addition of silver salt of either toluenesulfonate or chiral BINOL-phosphates generates active catalysts for the intramolecular cyclization of 6-methyl-1,1-diphenylhepta-4,5-dien-1-ol, where up to 47% ee can be obtained. Match and mismatch effects between chiral ligands and counteranions are highlighted.

The role of chiral counterions in gold-catalyzed asymmetric intramolecular hydroamination/hydroalkoxylation reactions of allenes and the oxidation state of the gold catalyst in the benzannulation of 2-carbonylphenylalkynes have been investigated using XAFS at the L3 edge of gold. Fitting of experimental data indicated a bond between cationic gold and a BINOL-phosphate anion in solution. 31P NMR confirmed that this phosphate group is likely not to be labile and may stay bonded to the gold catalyst during the catalytic cycle. In the benzannulation reaction, XAFS analysis suggested the majority of gold species obtained from reacting starting material with AuCl3 to be Au(III) complexes. NMR and mass spectrometry characterization led to the previously unobserved intermediate 10. gem-Diaurate complexes, which have been previously proposed as possible intermediates, were not detected.

Generation of catalytically active Pd(0) species from Pd(OAc)2 has been examined, in the context of Suzuki–Miyaura reactions involving substitution of aryl bromides under aerobic and ambient conditions. Using a combination of spectroscopic, microscopic and kinetic measurements, the role of each reaction component is delineated in the speciation of the palladium species. Among the key findings are the effects of O2, H2O and inorganic base, and implications for catalytic activity.

A series of 4,5-disubstituted γ-lactones, including whisky and cognac lactones, was synthesised in four steps from a readily available chiral precursor. By using an intramolecular hydroacylalkoxylation reaction in the final step, a correlation between the (E)/(Z) configuration of the precursor and the product distribution has been established, for the first time, in this type of cyclisation reactions.

Treatment of bimetallic palladacycles with silver perchlorate, followed by reaction with tertiary diphosphanes or diphenyl-2-pyridylphosphane gave novel dipalladium compounds with chelating [C,N,S], bridging [P,P], and chelating [P,P] or [P,N] ligands, as appropriate. The short-chain diphenyl-2- pyridylphosphane ligand forms stable four-membered P-N chelates, which display S-Pd-P and N-Pd-P trans geometries. The Pd-Cl bonds are nonreactive towards displacement by the [P,P] or [P,N] ligands, even in the case of strong chelating diphosphanes. New bimetallic palladacycles with bridging [P,P] and chelating [P,P], [P,N], and [C,N,S] donors are reported. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA.

Treatment of 4-MeOC6H4C(Me)═NN(H)C(═S)NHMe (1), with potassium tetrachloropalladate gave the tetranuclear compound [Pd{4-MeOC6H3C(Me)═NN═C(S)NHMe}]4 (2), with the ligand as terdendate [C,N,S]. Reaction of 2 with the diphosphines Ph2PCH2PPh2 (dppm), Ph2PC(═CH2)PPh2 (vdpp), and Ph2PC(CH2)2PPh2 (dpcp) gave the mononuclear complexes [Pd{4-MeOC6H3C(Me)═NN═C(S)NHMe}(L)] (L = dppm-P, 3; dpcp-P, 4; vdpp-P, 5) with the diphosphine ligand binding in a monodentate fashion. Compounds 3−5 may bond systematically to a second metal atom, palladium or platinum, through the noncoordinated phosphorus atom and the sulfur atom of the thiosemicarbazone moiety to give the dinuclear compounds 6−10, thus behaving as bidentate P,S-palladacycle metaloligands. All the compounds have been characterized by elemental analysis, and by IR and NMR spectroscopy; and the crystal and molecular structures of 1, 2, 6−10 have been determined by X-ray crystallography. Inter- and intramolecular hydrogen bonding in the solid results in crystal se...

Catalytic hydroamination reactions involving the addition of carboxamides (X = CO), carbamates (X = CO(2)) and sulfonamides (X = SO(2)) to unactivated C=C bonds are briefly reviewed. Development in this field of catalytic research is briefly charted, followed by a discussion of possible mechanisms, including arguments to support the operation of both metal and Brønsted acid catalysis in these systems. Future developments in the area are summarised.

Phosphine ligands continue to occupy a dominant position in homogeneous and asymmetric catalysis. In recent years, increasing availability of phosphine ligands and precursors from commercial sources has greatly facilitated the rapid discovery and optimisation of new catalytic processes. This Report ...

A terphenyl molecule consists of a central aromatic ring flanked by two other aryl groups, which may be arranged in 1,2 (ortho)-, 1,3 (meta)- or 1,4 (para)-configurations. Due to their conjugated π...

The reaction of the tetranuclear halide-bridged complexes 1−2(a−d) with Ph2PCH2PPh2 (dppm) or Ph2PC( CH2)PPh2 (vdpp) in 1:2 molar ratio and NH4PF6 afforded the novel tetarnuclear palladacycles 3−6 (a, c, d) as 1:2 electrolytes with bridging diphosphine and halogen ligands. The structure of 4a has been determined by X-ray diffraction analysis, and represents the first example of a tetranuclear palladacycle with bridging dppm and halogen ligands. Reaction of 1−2(a−d) with (Ph2PCH2CH2)2PPh (triphos) in 1:2 molar ratio gave 7(a−d) bearing two pentacoordinated palladium atoms. The structure of 7a, as determined by X-ray diffraction analysis, shows the distorted square pyramidal geometry around the metal centers. Treatment of 1−2(a−d) with dppm, vdpp or Ph2PN(Me)PPh2 (dppma) in 1:4 molar ratio gave the dinuclear palladacycles 8−10(a−d) with a chelating diphosphine ligand at each metal center; further treatment of 9(a−c) with the nucleophiles pyrrolidine, piperidine, morpholine or 4-methyl-piperidine gave the Michael addition derivatives 11−12(a−c), 13b, 13c and 14c, promoted by the withdrawing effect of the palladacycle which activates the C CH2 double bond.

The reaction of 1-(2,5-dimethylbenzylidene)-3-ethylthiosemicarbazone and palladium acetate in acetic acid yields a trinuclear cyclometallated palladium(II) compound. Each thiosemicarbazone ligand is tridentate with the metal bonded to the carbon atom from the 2-methyl group, to the azomethine nitrogen and to the sulfur atom, which bridges to an adjacent palladium center. The crystal structure confirms the presence of a non-planar hexagonal metallated ring plus a central six-membered palladium–sulfur core within the trimer, which also displays a rather deep intramolecular cavity.

Treatment of thiosemicarbazones (OC4H3)C(Me)= NN(H)C(=S)NHR (R: Me, a; Et, b) with [cis-PtMe2(cod)] afforded the tetranuclear compounds [Pt{(OC4H2)C(Me)=NN=C(S)NHR}] 4 (R: Me, 1a; Et, 1b). The reaction of la and lb with triphenylphosphine in 1:4 molar ratio gave rise to the mononuclear compounds [Pt{(OC4H2)C(Me)=NN=C(S)NHR)(PPh3)] (2a, 2b). Treatment of la and lb with large-bite diphosphines Ph2P(CH 2)nPPh2 (n = 2, dppe; n = 3, dppp; n = 4, dppb) afforded the dinuclear compounds [{Pt[(OC4H2)C(Me) = NN=C(S)NHR]}2{μ-Ph2P(CH2) nPPh2}], (3a-5a, 3b-5b), with the diphosphine in a bridging mode. Similar reactions with the short-bite diphosphines Ph 2PCH2PPh2 (dppm) and Ph2PC(=CH 2)PPh2 (vdpp) yielded the mononuclear compounds [Pt {(OC4H2)C(Me)=NN=C(S)NHR}-(Ph2PCH 2PPh2-P)] (6a, 6b) and [Pt{(OC4H 2)C(Me)=NN=C(S)NHR}(Ph2P-C(= CH2)PPh 2-P)] (7a, 7b) with the diphosphine in a monodentate coordination. Treatment of la and lb with [W(CO)5(Ph2CH 2PPh2)] gave the novel heterodinuclear species [{Pt[(OC4H2)C(Me)=NN= C(S)NHR]}[W(CO)5(Ph 2CH2PPh2-P)}] (8a, 8b), which could also be synthesized by reaction of 6a and 6b with [W(CO)5(THF)], 1H, 31P-{1H} and 13C-{1H} NMR and IR data are given. The crystal structure of compound 3b has been determined by X-ray crystallography. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.

A synthetic procedure was developed that enables sequential chemoselective Suzuki-Miyaura cross-coupling of chlorobromobenzene with arylboronic acids. The first coupling is achieved at room temperature using a ligandless palladium catalyst. The chlorobiaryl product can then be subjected directly to the second coupling, facilitated by the SPhos ligand. Using this methodology, parallel synthesis of 32 unsymmetrical o-, m-, and p-terphenyl compounds was accomplished in good to excellent overall yields.

The electronic and redox properties of a series of cyclometalated Pd complexes with oxidation states of +2, +3 and +4 were examined using a range of currently available spectroscopic and electrochemical techniques. Changes in metal–ligand bond lengths were established by X-ray crystallography and correctly predicted by DFT calculations, from which the frontier orbitals and partial atomic charges can be obtained. X-ray absorption spectroscopy (XAS) revealed interesting XANES features that suggest a synergistic relationship between metal–ligand interactions. The electrochemical study of the Pd(II) dimer was found to contain two sequential oxidative potentials indicative of a weak metal–metal interaction.

Treatment of the thiosemicarbazones 2-ClC6H4C(Me){double bond, long}NN(H)C({double bond, long}S)NHR, (R: Me, a; Et, b) and 2-BrC6H4C(Me){double bond, long}NN(H)C({double bond, long}S)NHR (R: Me, c; Et, d) with lithium tetrachloropalladate(II) in methanol or palladium(II) acetate in acetic acid gave the tetranuclear cyclometallated complexes [Pd{2-XC6H3C(Me){double bond, long}NN{double bond, long}C(S)NHR}]4 (X/R: Cl/Me, 1a; Cl/Et, 1b; Br/Me, 1c; Br/Et, 1d). Reaction of 1a-1d with bis(diphenylphosphino)methane, Ph2PCH2PPh2, in a 1:4 molar ratio and concentrated hydrochloric acid gave the mononuclear complexes [Pd{2-XC6H3C(Me){double bond, long}NN(H)-C({double bond, long}S)NHR}(Ph2PCH2PPh2-P,P)](Cl) (2a-2d). Reaction of 1a-1d with bis(diphenylphosphino)methane, Ph2PCH2PPh2, in 1:2 and 1:4 molar ratios gave the dinuclear or mononuclear complexes [{Pd[2-XC6H3C(Me){double bond, long}NN{double bond, long}C(S)NHR]}2(μ-Ph2PCH2PPh2)] (3a-3d), and [Pd{2-XC6H3C(Me){double bond, long}NN{double bond, long}C(S)NHR}(Ph2PCH2PPh2-P)] (4a-4d), with bridging and chelating diphosphine, respectively. The molecular structures of complexes 1b, 1d, 4c and 4d have been determined by X-ray diffraction analysis. © 2006 Elsevier Ltd. All rights reserved.

The reaction of the thiosemicarbazone ligands 1-(COMe)-3-[C(H)=NN(H)C(=S) NHR]C 8 H 5 N, (R = H a, Me b, Et c) with potassium tetrachloropalladate in an ethanol/water mixture led to the new tetranuclear palladium(II) compounds [Pd{1-(COMe)-3-[C(H)=NN=C(S)NHR]C 8 H 4 N-k 3 C5,N,S}] 4 (R = H 1a, Me 1b, Et 1c) which contain six-membered metallacycles. The thiosemicarbazone ligands in these complexes are terdentate through the C, N, and S atoms and are deprotonated at the NH group. The Pd-S bond formed is sufficiently strong to undergo reactions with nucleophiles without bond cleavage. Reaction of 1a and 1b with 1,2-bis(diphenylphosphanyl)ethane (dppe) gave the dinuclear species [{Pd[1-(COMe)-3-{C(H)=NN=C(S)NHR}C 8 H 4 N]} 2 (μ-Ph 2 P(CH 2 ) 2 PPh 2 )] (R = H 2a, Me 2b). The molecular structure of complex 1b has been determined by X-ray diffraction analysis. © Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Treatment of the thiosemicarbazones 4-FC6H4C(Me) NN(H)C( S)NHR, (R = Me, a; Ph, b) and 2-ClC6H4C(Me) NN(H)C( S)NHR (R = Ph, c) with lithium tetrachloropalladate(II) in methanol or palladium(II) acetate in acetic acid gave the tetranuclear cyclometallated complex [Pd{4-FC6H3C(Me) NN C(S)NHR}]4 (1a, 1b) and [Pd{2-ClC6H3C(Me) NN C(S)NHPh}]4 (1c). Reaction of these tetramers with the diphosphines dppe, t-dppe, dppp or dppb in a 1:2 molar ratio gave the dinuclear cyclometallated complexes [(Pd{4-FC6H3C(Me) NN C(S)NHR})2(μ-Ph2P(CH2)nPPh2)], (n = 2, 2a, 2b; 3, 4a, 4b; 4, 5a, 5b), [(Pd{4-FC6H3C(Me) NN C(S)NHPh})2(μ-Ph2PCH CHPPh2)], (3a, 3b) and [(Pd{2-ClC6H3C(Me) NN C(S)NHR})2(μ-Ph2P(CH2)nPPh2)], (n = 2, 2c, 2d; 3, 4c, 4d; 4, 5c, 5d), [(Pd{2-ClC6H3C(Me) NN C(S)NHPh})2(μ-PPh2CH CHPPh2)], (3c, 3d). The X-ray crystal structure of the ligand b and the complexes 3c, 4a and 4d were determined. The structures of complexes 4a and 4d show that the different disposition of the chain cyclometallated of the thiosemicarbazones (in the same orientation or in the opposite one) is due to the different H bonds produced.

The reaction of the thiosemicarbazones (η5-C5H5)Fe(η5-C5H4)C(H) NN(H)C( S)NHR (R = H, a; R = Me, b) with K2PdCl4 afforded octanuclear cyclometallated complexes [Pd{(η5-C5H5)Fe(η5-C5H3)C(H) NN C(S)NHR}]4 (R = H, 1a; R = Me, 1b). Reaction of complexes 1a and 1b with tertiary diphosphines in 1:2 molar ratio and subsequent recrystallization from CH2Cl2/n-C6H14 gave rise to tetranuclear complexes [{Pd[(η5-C5H5)Fe(η5-C5H4)C(H) NN C(S)NHR](Cl)}2(μ-Ph2P(CH2)nPPh2)] (R = H, n = 4, 2a; R = Me, n = 1, 2b; n = 4, 3b). Treatment of complexes 1a and 1b with tertiary monophosphines in 1:4 molar ratio and subsequent recrystallization from CH2Cl2/n-C6H14 gave rise to dinuclear complexes [Pd{(η5-C5H5)Fe(η5-C5H4)C(H) NN C(S)–NHR}(Cl)(P)] (R = H: P = PPh3, 3a; P = PPh2Et, 4a; P = P(C6D5)3, 5a; R = Me: P = PPh3, 4b; P = PPh2Et, 5b; P = P(C6D5)3, 6b). The crystal structures of 2a and 2b have been determined by X-ray crystallography.

Reaction of the thiosemicarbazone ligands C4H4NC(H)=NN(H)C(S)NHR (R = Me, a; Et, b) with Li2[PdCl4] gave the dinuclear complexes [Pd{C4H4NC(H)=NNC(S)NHR}(μ-Cl)]2 (R = Me, 1a; Et, 1b) with a central Pd2Cl2 core and with deprotonation of the thiosemicarbazones at the hydrazinic nitrogen atom. Treatment of 1a and 1b with triphenylphosphine gave the mononuclear compounds [Pd{C4H4C(H)=NNC(S)NHR}(Cl)(PPh3)] (R = Me, 2a; Et, 2b), whereas reaction of 1a and 1b with tertiary diphosphines gave mono- and dinuclear compounds, as appropriate, with the corresponding diphosphine acting as a monodentate (6b), chelating (3a) and bridging ligand (4a, 5a, 4b, 5b). Treatment of 1a and 1b with (Ph2PCH2CH2PPh2)W(CO)5 gave the new heterobimetallic complexes 7a and 7b. The crystal structures of complexes 3a and 4a are described.

Treatment of the thiosemicarbazone 2-FC6H4C(Me)= NN(H)C(=S)NHPh, a, with palladium(II) acetate in acetic acid, or with lithium tetrachloropalladate(II) in methanol, gave the tetranuclear cyclometallated complex [Pd{2-FC6H3C(Me)=NN= C(S)NHPh}]4 (1a). Reaction of 1a with the diphosphines Ph2P(CH2) 2PPh2 (dppe), Ph2PCH=CHPPh2 (trans-dpe) Ph2P(CH2)3Ph2 (dppp) or Ph2P(CH2)4Ph2 (dppb) in a 1:2 molar ratio gave the dinuclear cyclometallated complexes [(Pd{2-FC6H 3C(Me)=NN=C(S)NHPh})2(μ-Ph2P(CH 2)nPPh2)], (n = 2, 2a; 3, 4a; 4, 5a) and [(Pd{2-FC6H3C(Me)=NN=C(S)NHPh})2(μ-Ph 2PCH=CHPPh2)], (3a). The X-ray crystal structure of ligand a and of complex 2a are described. The structure of complex 2a shows the palladium atom is bonded to four different donor atoms: C, N, S and P. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.

A custom-made plug flow reactor was designed and constructed to examine the behaviour of Pd catalysts during Suzuki-Miyaura cross-coupling reactions. Spatial-temporal resolution of catalyst activation, deactivation and leaching processes can be obtained by single-pass experiments. Subsequent deployment of the flow reactor in a XAS beam line revealed speciation of Pd along the catalyst bed.

The direct addition of O-H bonds to C=C bonds is a very attractive way of synthesising alcohols, ethers and esters, due to the inherent atom- and step-economy of the process. This microreview focuses on the development of group 11 metal catalysts in mediating these transformations. Bronsted acid catalysis has been shown to play a role in some of these processes, and this is highlighted where appropriate. The utility of these methods in organic synthesis is addressed through selected examples. The direct addition of O-H bonds to C=C bonds is an attractive way to synthesise alcohols, ethers and esters. This microreview addresses the use of group 11 metals in promoting these transformations. The involvement of Bronsted acid catalysis in some of these reactions is highlighted. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

(R)-4,12-Bis(diphenylphosphino)-[2.2]-paracyclophane [364732-88-7] C40H34P2 (MW 576.65) InChI = 1S/C40H34P2/c1-5-13-35(14-6-1)41(36-15-7-2-8-16-36)39-29-31-21-25-33(39)27-23-32-22-26-34(28-24-31)40(30-32)42(37-17-9-3-10-18-37)38-19-11-4-12-20-38/h1-22,25-26,29-30H,23-24,27-28H2 InChIKey = GYZZZILPVUYAFJ-UHFFFAOYSA-N Physical Data: white solid, mp 222–226 °C. [α]d = −34 ± 4° (c 1, CHCl3). (S)-4,12-Bis(diphenylphosphino)-[2.2]-paracyclophane [192463-40-4] InChI = 1S/C40H34P2/c1-5-13-35(14-6-1)41(36-15-7-2-8-16-36)39-29-31-21-25-33(39)27-23-32-22-26-34(28-24-31)40(30-32)42(37-17-9-3-10-18-37)38-19-11-4-12-20-38/h1-22,25-26,29-30H,23-24,27-28H2 InChIKey = GYZZZILPVUYAFJ-UHFFFAOYSA-N Physical Data: white solid, mp 222–226 °C. [α]22d = +34° (c 1, CHCl3) (used as a chiral diphosphine ligand in transition metal-catalyzed reactions and also as organocatalyst) Solubility: not reported. Form Supplied in: white solid. Commercially available. Handling, Storage, and Precautions: readily oxidized to the phosphine oxide in solution and should be handled under N2 or Ar. Solid samples can be handled in air. Avoid contact with strong oxidizing agents and halogens.

A terphenyl molecule consists of a central aromatic ring flanked by two other aryl groups, which may be arranged in 1,2 (ortho)-, 1,3 (meta)- or 1,4 (para)-configurations. Due to their conjugated π...

Intramolecular cyclisation of ω-alkenoic acids and alkenols can be achieved using a catalytic amount of Cu(OTf)2 to afford lactones and cyclic ethers, offering a practical alternative to existing catalysts.

Air- and moisture-stable Cu(OTf)2–bipy catalyses the addition of phenols to 1,3-dienes under aerobic conditions in a tandem hydroalkoxylation–rearrangement–hydroalkylation sequence, furnishing O-heterocycles in moderate to good yields, and can be recycled without any loss in catalytic activity.

Incorporation of a hemilabile amino group with a bulky, electron-rich phosphorus ligand led to a reversal in the order of aryl bromide reactivity in Pd-catalysed aryl amination reactions.

The inexpensive and commercially available catalytic system RuCl3·nH2O-NaOAc-Zn is active in water for the direct C-H arylation of arenes with aryl/heteroaryl chlorides. The reaction can be accelerated by the use of microwave irradiation and can also be scaled up to a multi-gram scale with excellent isolated yields.

Air- and moisture-stable Cu(OTf)(2)-bipy catalyses the addition of phenols to 1,3-dienes under aerobic conditions in a tandem hydroalkoxylation-rearrangement-hydroalkylation sequence, furnishing O-heterocycles in moderate to good yields, and can be recycled without any loss in catalytic activity.