The 9-amino(9-deoxy)epi cinchona alkaloids have expanded the synthetic potential of asymmetric aminocatalysis, enabling highly stereoselective functionalization a variety sterically hindered carbonyl compounds. However, there is lack basic understanding mechanisms cinchona-based primary aminocatalysis. Herein, we describe how combination experimental and theoretical mechanistic studies has revealed origin stereoselectivity Friedel–Crafts alkylation indoles with α,β-unsaturated ketones...

A Cp*CoIII -catalyzed C-H functionalization of benzamide substrates with α,β-unsaturated ketones has been optimized, providing a facile route towards aliphatic ketone products. When employing aldehydes as coupling partners, under the optimized protocol, cascade reaction forming azepinones also developed. Finally, DFT studies have demonstrated how stabilization metallo-enol intermediate when is driving force leading to observed product rather than olefinic products reported using esters partners.

A new boron-based flexible scorpionate ligand based upon 7-azaindole, Li[Ph(H)B(azaindolyl)2] (Li[PhBai]), has been prepared. This ligand, together with the previously reported K[HB(azaindolyl)3] (K[Tai]), have used to prepare a range of monovalent group 9 transition-metal complexes. The complexes [M(COD){κ3N,N,H-Ph(H)B(azaindolyl)2}] (where M = rhodium, iridium and COD 1,5-cyclooctadiene) [Rh(NBD){κ3N,N,H-HB(R)(azaindolyl)2}] NBD 2,5-norbornadiene R Ph, azaindolyl) Structural...

The reaction of Ir(COD)(Tai) [where Tai = {HB(7-azaindoyl)3}−] with carbon monoxide results, via a sequence hydride migration and insertion steps, in the formation first complexes to contain metal-to-boron dative interaction supported by 7-azaindole units.

A series of gold( i ) and silver( complexes 1,2,4-triazolylidene imidazolylidene based N-heterocyclic carbene ligands were prepared that show excellent antibacterial activity against clinically relevant bacterial pathogens.

[InBr(salphen)] is identified as the most active catalyst for conversion of CO 2 and epoxides to cyclic carbonates compared Al Ga congeners. The elucidated mechanism highlights importance both Lewis acidity ligand fluxionality.

A new family of flexible scorpionate ligands based on 2-mercaptopyridine is reported. The tris- and bis-substituted ligands, K[HB(mp)3] (1) Na[H2B(mp)2] (2) (mp = 2-mercaptopyridine) have been prepared fully characterised. structural characterisation 1 reveals an unprecedented μ3-κ3-SS′H-η1η1η2-κ2-S″C-η1η1-κ1-S′-η1 coordination mode. both 2 to copper(I) complexes containing triphenylphosphine tricyclohexylphosphine co-ligands investigated suggesting κ3-SSS modes for [Cu{HB(mp)3}(PR3)] {where...

The coordination chemistry and ethene hydromethoxycarbonylation catalysis with the diphosphine o-C6H4(CH2PtBu2)(CH2PPh2) (L3) is reported results compared analogous of symmetrical diphosphines o-C6H4(CH2PtBu2)2 (L1) o-C6H4(CH2PPh2)2 (L2). Palladium-catalyzed studies under commercial catalytic conditions are reported. obtained using L1−3 as supporting ligands show that catalysts derived from L3 L1 have similar activity selectivity for methyl propanoate (MeP). In addition, Pd−L3 catalyst has...

We describe the synthesis of a bisporphyrin tweezer receptor 1·H(4) and its metalation with Zn(II) Rh(III) cations. report thermodynamic characterization supramolecular chirality induction process that takes place when metalated receptors coordinate to enantiopure 1,2-diaminocyclohexane in two different solvents, toluene dichloromethane. also performed thorough study several simpler systems were used as models for more complex systems. The initial complexation chiral diamine bisporphyrins...

Abstract Application of a binary Ga‐based catalyst system for the coupling CO 2 and aziridines to form oxazolidinones is presented. It has been possible optimize selective formation single regioisomer, in excellent yield, under relatively mild reaction conditions. The optimized successfully applied range substituted derived from styrene oxide. observed that bearing two aromatic substituents result piperazine through an unexpected dimerization reaction. These products can be selectively...

A new boron-based hybrid scorpionate ligand based upon one 2-mercaptopyridine (mp) and two 1-methyl-imidazoyl-2-thione (mt) units, Na[HB(mt)(2)(mp)] has been prepared. This together with the recently reported K[HB(mp)(3)] have used to prepare analogues of original metallaboratrane complex [Ru(CO)(PPh(3)){kappa(4)-SSBS-B(mt)(3)}]. The effect tautomerisation arms electronic properties boron metal centres is examined in an attempt probe further nature metal-boron bond within complexes.

An unusual ruthenium(ii) complex frozen at an intermediate point of hydride transfer between boron and ruthenium centres is reported.

The first structurally characterised zerovalent platinum complex to contain a tridentate pincer-type coordination mode (kappa(3)-SBS) is presented, raising further questions concerning the geometries and trans influence of Z-type ligands.

The synthesis and characterization of the first platinum group metal complexes recently reported ligand [H2B(mp)2]− (where mp = 2-mercaptopyridyl) are presented herein. Addition 2 equiv Na[H2B(mp)2] to [MCl(COD)]2 M Rh, Ir; COD 1,5-cyclooctadiene) leads hydride migration products [Rh{κ3-SSB-BH(mp)2}(η3-C8H13)] [Ir(H){κ3-SSB-BH(mp)2}(η4-C8H12)], respectively. Structural rhodium complex reveals a notably short rhodium–boron distance 2.054(2) Å. reactivity observed for is different from that...

The following unsymmetrical diphosphines have been prepared: o-C6H4(CH2PtBu2)(PR2) where R = PtBu2 (L3a); PCg (L3b); PPh2 (L3c); P(o-C6H4CH3)2 (L3d); P(o-C6H4OCH3)2 (L3e) and o-C6H4(CH2PCg)(PCg) (L3f) is 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamant-6-yl. Hydromethoxycarbonylation of ethene under commercially relevant conditions has investigated in the presence Pd complexes each ligands L3a–f results compared with those obtained used o-C6H4(CH2PtBu2)2 (L1a). bulkiest L3a, L3b L3f are...

Abstract This work reports on the use of gallium aminotrisphenolate compounds as catalysts for synthesis cyclic carbonates from epoxides and CO 2 . The results show that they are highly active, more so than corresponding aluminium congeners. catalyst system is applicable at low elevated temperatures across a wide substrate scope including terminal, internal, multiple fully deuterated epoxides. Applying loadings has allowed TON 344,000 to be obtained, highlighting their stability. A DFT...

Rhodium and iridium complexes of flexible scorpionate ligands based on azaindole were synthesised in good yields. The characterised solution the solid state. Structural characterisation revealed a B–H–metal interaction, which is retained solution. Given greater flexibility ligand potential cooperative effect boron, tested for their activity transfer hydrogenation ketones.

Three methods for the large scale (50−100 g) separation of secondary phobanes 9-phosphabicyclo[3.3.1]nonane (s-PhobPH) and 9-phosphabicyclo[4.2.1]nonane (a-PhobPH) are described in detail. Selective protonation s-PhobPH with aqueous HCl presence a-PhobPH is an efficient way to obtain quantities a-PhobPH. oxidation acidified mixture s-PhobPH. The crystalline, air-stable phosphonium salts [s-PhobP(CH2OH)2]Cl [a-PhobP(CH2OH)2]Cl can be separated by a selective deformylation NaOH. shown...

The synthesis and properties of a series unsymmetrical diphosphines o-C6H4(CH2PtBu2)(CH2PR2) are reported where R = C6H5 (La); p-CH3C6H4 (Lb); o-CH3C6H4 (Lc); o-CH3CH2C6H4 (Ld); o-CH3OC6H4 (Le); 2,4,6-(CH3)3C6H4 (Lf); CH(CH3)2 (Lg); or PR2 PCg (Lh) is 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamant-6-yl. Hydromethoxycarbonylation ethene under commercially relevant conditions catalysed by the Pd complexes each ligands La–ha–h to give methyl propanoate in >99% selectivity with catalytic...

Abstract 1,2,3‐benzotriazin‐4(3 H )‐one derivatives have been recognised for their potential application as pesticides and pharmaceuticals new methodologies preparation, starting from readily accessible reagents would therefore be an attractive proposition. A wide range of differently substituted benzamides are available, which provide excellent substrate scaffold the direct C−H functionalization protocols. In this context, herein we report use a Cp*Co(III) catalyst amidation these...

Calixarene 0118 (OTX008) and chrysin (CHR) are promising molecules for the treatment of fibrosis diabetes complications but require an effective delivery system to overcome their low solubility bioavailability. Sulfobutylated β-cyclodextrin (SBECD) was evaluated its ability increase CHR by forming a ternary complex with OTX008. The resulting in mechanisms formation were identified through phase-solubility studies, while dynamic light-scattering assessed molecular associations within...

Abstract The synthesis, characterization and application of a new complex, [Ir(κ 2 ‐ P,N 6‐D Cy Pon * )(COD)] ( 1 ), where is the anionic species, 6‐dicyclohexylphosphino‐2‐oxo‐pyridinide, reported herein. Complex was found to be an active catalyst in hydrogenation CO at room temperature. ligand, Pon* , derived via deprotonation novel pro‐ligand, (6‐dicyclohexylphosphino‐2‐pyridone) during synthesis . ligand shown participate within reversible cooperative process, which [IrH 3 (κ...

Abstract The synthesis of bio‐derived cyclic carbonates is attracting a lot attention as the incorporation functionality into these compounds provides opportunity to prepare previously unknown structures, whilst also improving their sustainability profiles. This study presents facile preparation diastereomerically pure displaying range optical rotation values. These are obtained from glycidol, amino acids and CO 2 in two‐step approach. Initially, acid functionalised epoxides prepared through...

The reaction of a mixture the sodium salts dihydrobis(4-ethyl-3-methyl-5-thioxo-1,2,4-triazolyl)borate, NaBt, and hydrotris(4-ethyl-3-methyl-5-thioxo-1,2,4-triazolyl)borate, NaTt, with [{Rh(cod)(μ-Cl)}2] gave [Rh(cod)Bt] [Rh(cod)Tt], which separately react CO gas to give unstable dicarbonyl [Rh(CO)2Bt] an equilibrium two isomers [Rh(CO)2Tt] [(RhTt)2(μ-CO)3], respectively. Tertiary phosphorus donor ligands [(RhTt)2(μ-CO)3] [Rh(CO)(PR3)Tt] (R = Cy, NMe2, Ph or OPh) [Rh{P(OPh)3}2Tt] in rhodium...

The reaction of potassium hydrotris(methimazolyl)borate {KTm = HB(mt)(3)} with [{Rh(cod)(mu-Cl)}(2)] gave [Rh(cod)Tm] while the complexes [Rh(CO)(PR(3))Tm] (R Ph or NMe(2)) and [Rh{P(OPh)(3)}(2)Tm] were isolated from light-sensitive [Rh(CO)(2)Tm], prepared in situ KTm [{Rh(CO)(2)(mu-Cl)}(2)], PR(3) P(OPh)(3) under CO. adopt kappa(3)-S(2)H structures solid state but all cases rapid dynamic exchange processes render three mt rings equivalent solution. Oxidation [Rh(CO)(PPh(3))Tm]...