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An efficient method for the C-N cross-coupling of (hetero)aryl (pseudo)halides with optically pure [alpha]-amino acid esters employing a commercially available nickel catalyst and weak inorganic base was developed. This is the first example of Nicatalyzed N-arylation of amino acid esters without the use of electrochemistry, which was shown to effectively couple a variety of amino acid tert-butyl esters with (hetero)aryl chlorides, bromides, and tosylates in high yields and excellent enantioretention. Base-mediated racemization was revealed during control experiments, but increasing the steric bulk of the amino acid ester group limited the amount of racemization of the product. Key words: amination, cross-coupling, amino acid esters, nickel, Introduction Transition metal catalysis is widely employed for cross-coupling reactions in modern synthetic organic chemistry, enabling the development of complex molecules from readily available starting materials. The development of catalysts [...]

This article explores the recent advancements in nickel-catalyzed C-O cross-coupling reactions, specifically focusing on the use of aliphatic alcohols and phenols as nucleophiles. The authors discuss different catalytic systems and methodologies that have been developed, including the use of photoredox and electrochemical processes. The article highlights the expanding scope and utility of these reactions, as well as the potential for more environmentally friendly synthetic methods in the future. [Extracted from the article]

We disclose herein our study examining the potential activating effect of added aluminum triflate (5 mol %) on the (DalPhos)Ni(aryl)Cl (1 mol % Ni) catalyzed C−N cross‐coupling of primary amides with (hetero)aryl chlorides. In some instances, dramatically improved conversion to product was achieved by use of added aluminum triflate; with furfurylamine catalytic inhibition occurred. The reaction outcome appears to result from the interplay of DalPhos ligand and aryl group within the Ni pre‐catalyst, as well as the identity of the cross‐coupling partners. [ABSTRACT FROM AUTHOR]

The present contribution describes the systematic structural diversification of the [[KAPPA].sup.2]-P,N DalPhos ligand family in an effort to improve catalytic efficiency in the monoarylation of ammonia and acetone. The study is focused primarily on modifying the backbone phenylene linker, while retaining the same bite angle and steric bulk as the Mor-DalPhos ligand through the use of P[(1-Ad).sub.2] and morpholine donors. Eight new variants of Mor-DalPhos were prepared; two of these feature a pyridine linker (L1, L2), and five others feature either electron-donating (L3, L4) or electron-withdrawing (L5-L7) substituents on the phenylene linker. Additionally, thiomorpholino substitution (L8) was performed to investigate the effects of a possible tridentate coordination mode. Precatalyst complexes of the general formula LPd(cinnamyl)Cl were prepared and characterized in both solution and solid state. Solution studies demonstrated a significant degree of lability in the Pd-N bond, whereby dynamic behavior is seen to be dependent on the nature of the ligand backbone. The utility of these new ligands in the palladium-catalyzed monoarylation of ammonia or acetone was then surveyed. Notably, pyridine-derived ligand variants (L1, L2) were observed to out-perform parent Mor-DalPhos in the latter transformations. Key words: amination, catalysis, cross-coupling, ligand design, palladium. Dans la presente contribution, nous decrivons la diversification structurale systematique de la famille de ligands [[kappa].sup.2]-P,N-DalPhos en vue d'ameliorer l'efficacite catalytique de la monoarylation de l'ammoniaque et de l'acetone. Dans cette etude, nous nous sommes principalement interesses a modifier l'espaceur phenylene du squelette du ligand Mor-DalPhos, tout en conservant le meme angle de chelation et le meme encombrement sterique, en utilisant des phosphines de structure P[(1-Ad).sub.2] portant un donneur de type morpholine. Nous avons prepare huit nouvelles variantes du ligand Mor-DalPhos; dont deux presentent un espaceur de type pyridine (L1, L2) et les cinq autres, des substituants soit electrodonneurs (L3, L4) ou electroattracteurs (L5-L7) disposes sur l'espaceur phenylene. De plus, nous avons realise une substitution par le groupe thiomorpholine (L8) pour examiner les effets d'un possible mode de coordination tridentate. Nous avons prepare les complexes precatalytiques de formule generale LPd(cinnamyl)Cl et les avons caracterises en solution comme a l'etat solide. Selon les resultats des experiences en solution, la liaison Pd-N a revele un degre de labilite important, lequel est determine par la nature du squelette du ligand dont semble dependre le comportement dynamique. Nous avons explore l'utilite de ces nouveaux ligands dans les monoarylations de l'ammoniaque et de l'acetone catalysees par le palladium, dans lesquelles nous avons notamment observe que les analogues du ligand derives de la pyridine (L1, L2) presentaient un meilleur rendement qu'avec le ligand Mor-DalPhos d'origine. [Traduit par la Redaction] Mots-cles : amination, catalyse, couplage croise, conception de ligand, palladium., Introduction The development of new classes of ancillary ligands, such as tertiary monodentate/bidentate (bis)phosphines (1-4) and N-heterocyclic carbenes (NHCs), (5-8) has permitted great advancements in the scope and efficiency of [...]

The competitive catalytic screening of 18 known and newly prepared Mor-DalPhos ligand variants in the palladium-catalyzed cross-coupling of chlorobenzene with aniline, octylamine, morpholine, indole, ammonia, or acetone is presented, including ligands derived from the new secondary phosphine HP([[sup.Me2]Ad).sub.2] ([sup.Me2]Ad = 3,5-dimethyladamantyl). Although triarylphosphine ancillary ligand variants performed poorly in these test reactions, ligands featuring either [PAd.sub.2] or P[([sup.Me2]Ad).sub.2] donors (Ad = 1-adamantyl) gave rise to superior catalytic performance. Multiple Mor-DalPhos variants proved effective in cross-couplings involving aniline, octylamine, or morpholine; conversely, only a smaller subset of ligands proved useful in related cross-couplings of indole, ammonia, or acetone. In the case of the N-arylation of indole, a Mor-DalPhos ligand variant featuring ortho-disposed [PAd.sub.2] and dimethylmorpholino donor fragments (L13) proved superior to all other ligands surveyed, including the parent ligand Mor-DalPhos (L5). Conversely, L5 was found to be superior to all other ligands in the palladium-catalyzed monoarylation of ammonia. Ligand L6 (i.e., the P[([sup.Me2]Ad).sub.2] variant of L5) proved superior to all other ligands in the monoarylation of acetone and, with the exception of indole N-arylation, was the most broadly useful of the Mor-DalPhos ligands surveyed herein. Key words: amination, cross-coupling, ligand design, palladium. Nous présentons le criblage catalytique compétitif de 18 nouvelles variantes du ligand Mor-DalPhos que nous avons préparées en soumettant le chlorobenzène au couplage croisé catalysé par le palladium avec l'aniline, l'octylamine, la morpholine, l'indole, l'ammoniac ou l'acétone. Parmi ces variantes figurent des ligands dérivés des phosphines secondaires HP[([sup.Me2]Ad).sub.2] ([sup.Me2]Ad = 3,5-diméthyladamantyl) nouvellement synthétisées. Bien que les variantes de ligands auxiliaires dérivés de triarylphosphines aient produit de piètres résultats dans ces essais réactionnels, les ligands présentant des donneurs à base de [PAd.sub.2] ou de P[([sup.Me2]Ad).sub.2] (Ad = 1-adamantyl) ont offert une performance catalytique supérieure. Plusieurs variantes du Mor-DalPhos se sont montrées efficaces pour effectuer les couplages croisés avec l'aniline, l'octylamine ou la morpholine. À l'inverse, seul un petit sous-ensemble de ligands s'est révélé utile dans les couplages croisés correspondants avec l'indole, l'ammoniac ou l'acétone. Dans le cas de la N-arylation de l'indole, une variante du ligand Mor-DalPhos présentant les groupements donneurs à base de [PAd.sub.2] et de diméthylmorpholine disposés en ortho (L13) s'est révélée supérieure à tous les autres ligands étudiés, y compris le ligand Mor-DalPhos d'origine (L5). Inversement, le ligand L5 s'est montré supérieur à tous les autres ligands pour effectuer la monoarylation de l'ammoniac catalysée par le palladium. Le ligand L6 (c.-à-d. la variante du ligand L5 présentant la P[([sup.Me2]Ad).sub.2] s'est montré supérieur à tous les autres ligands à l'égard de la monoarylation de l'acétone. De plus, ce ligand était le plus polyvalent, hormis la N-arylation de l'indole, parmi les ligands dérivés du Mor-DalPhos étudiés dans le cadre de ces travaux. [Traduit par la Rédaction] Mots-clés: amination, couplage croisé, conception de ligand, palladium., Introduction Palladium-catalyzed cross-coupling of (hetero)aryl (pseudo)halides and NH substrates (i.e., Buchwald--Hartwig amination, BHA1) has emerged as a remarkably useful protocol for the synthesis of (hetero)anilines. The critical role that ancillary [...]

The mono‐α‐arylation of 2‐tetrahydropyranyl O‐protection of hydroxyacetone is reported. When using a catalyst system comprised of [Pd(cinnamyl)Cl]2 and the JosiPhos ligands PhPF‐tBu or (4‐CF3Ph)PF‐tBu, such transformations are achieved with ortho‐substituted aryl bromides and triflates in the presence of potentially contending functionalities including chloro groups. [ABSTRACT FROM AUTHOR]

We report herein on our synthetic, structural, and catalytic investigations of new P,S-DalPhos ligands featuring pairings of phosphorus and sulfur donor groups as well as new sulfur-containing analogues of the previously reported P,N-ligands Me-DalPhos and Mor-DalPhos, featuring a 2,3-disubstituted thiophenyl backbone. In examining the catalytic performance of these new sulfur-containing ligands in the Buchwald-Hartwig amination of octylamine, aniline, or ammonia with 4-chlorotoluene, noteworthy differences in reactivity behavior relative to Me-DalPhos and Mor-DalPhos were observed. Key words: amination, cross-coupling, ligand design, palladium. Nous presentons ici les etudes catalytique, structurale et de la synthese que nous avons realisees sur de nouveaux ligands P,S-DalPhos comportant des appariements entre groupes donneurs a base de soufre et groupes donneurs a base de phosphore et sur de nouveaux analogues des P,N-ligands Me-DalPhos et Mor-DalPhos precedemment decrits, qui contiennent du soufre et comportent une chaine principale de 2,3-thiophenyl disubstitue. En examinant le rendement catalytique de ces nouveaux ligands a base de soufre lors de l'amination de Buchwald-Hartwig d'octylamine, d'aniline ou d'ammoniac en presence de 4-chlorotoluene, on a observe des differences notables de reactivite liee au Me-DalPhos et au Mor-DalPhos. [Traduit par la Redaction] Mots-cles: amination, reaction de couplage, conception de ligands, palladium., Introduction Palladium-catalyzed amine arylation by use of (hetero)aryl (pseudo)halides (i.e., Buchwald-Hartwig amination (BHA) (1-2)) has evolved into a powerful tool for the synthesis of aniline derivatives, with applications in the [...]

A systematic competitive evaluation of the DalPhos ligand family in nickel‐catalyzed N‐arylation chemistry is reported, involving primary (linear and branched) and secondary alkylamines, as well as a primary five‐membered heteroarylamine (aminopyrazole), in combination with a diverse set of test electrophiles and bases (NaOtBu, K2CO3, DBU/NaTFA). In addition to providing optimal ligand/catalyst identification, and bringing to light methodology limitations (e. g. unwanted C−O cross‐coupling with NaOtBu), our survey enabled the development of the first efficient catalyst system for heteroatom‐dense C−N cross‐coupling of aminopyrazoles and related nucleophiles with (hetero)aryl chlorides by use of an amine 'dual‐base' system. [ABSTRACT FROM AUTHOR]

We report herein on the synthesis and spectroscopic/crystallographic characterization of the first isolable, formally 16-electron Cp*Ru([κ.sup.2]-P~N) species, which are supported by N-phosphinoamidinate ligands. Despite the stability of such complexes, they have been shown to readily coordinate two-electron (L) donors including carbon monoxide and 2,6-xylylisocyanide, affording crystallographically characterized 18-electron Cp*Ru(L) ([κ.sup.2]-P~N) adducts. Preliminary reactivity studies confirm that such complexes are capable of extruding hydrogen from ammonia borane. Key words: N-phosphinoamidinate, ruthenium, ligand design, coordinative unsaturation. Nous decrivons la synthese et la caracterisation spectroscopique/cristallographique des premieres especes isolables Cp*Ru([κ.sup.2]-P~N) formellement a 16 electrons, qui sont supportees par des ligands N-phosphinoamidinate. Malgre leur stabilite, on a montre que ces complexes forment facilement une liaison de coordination avec des donneurs de doublet d'electrons (L), y compris le monoxyde de carbone et le 2,6-xylylisocyanure, pour donner des adduits Cp*Ru(L)([κ.sup.2]-P~N) a 18 electrons caracterises par cristallographie. Les etudes de reactivite preliminaires confirment que ces complexes sont capables d'extraire l'hydrogene de l'ammonia borane. [Traduit par la Redaction] Mots-cles: N-phosphinoamidinate, ruthenium, conception de ligands, insaturation coordinative., Introduction Coordinatively unsaturated Cp*Ru[L.sub.n] (Cp* = [η.sup.5]-[C.sub.5][Me.sub.5]) and related complexes have a well-established track record of exhibiting new and unusual metal-centered reactivity, (1, 2) with diverse applications in organic synthesis [...]

A series of [C.sub.6][Ph.sub.5]X compounds, including X = H, Br, C[O.sub.2]H, C[O.sub.2]R, C'CPh, ris-BrC=C(Br)Ph, 2- bornenyl, and ferrocenyl, have been characterized by use of X-ray crystallography. Also, the first organometallic complexes of pentaphenylbenzene have been prepared by reaction with chromium hexacarbonyl to yield ([η.sup.6]-[C.sub.6][Ph.sub.5]H)Cr[(CO).sup.3] complexes in which the metal tripod is attached either to an ortho peripheral ring or to the central ring. Crystalline pentaphenylbenzoic acid exists as a hydrogenbonded dimer; however, the steric bulk of the substituents does not allow the carboxylic acid moieties to be linked directly but instead via two bridging methanol molecules. In the solid state, the orientation of the peripheral rings in bulky [C.sub.6][Ph.sub.5]X systems is very sensitive to the size of the 'X' substituents, such that the twist angle of the para ring responds inversely with increasing bulk of 'X', which drives the ortho rings farther out of the plane of the central ring. The relevance of these observations to correlated motion in molecular propellers, and ultimately to molecular machines, is discussed. Key words: polyarylbenzenes, substituent orientations, rotational barriers, correlated rotations, arene chromium complexes. A l'aide de la cristallographie aux rayons X, on a caracterise une serie de composes de formule [C.sub.6][Ph.sub.5]X, ou X = H,Br, C[O.sub.2]H, C[O.sub.2]R, CCPh, ris-BrC=C(Br)Ph, 2-bornenyl et ferrocenyl. En outre, on a prepare les premiers complexes organometalliques du pentaphenyl-benzene en le faisant reagir avec de l'hexacarbonyle de chrome pour obtenir les complexes ([η.sup.6]-[C.sub.6][Ph.sub.5]H)Cr[(CO).sub.3] dans lesquels le tripode metallique est attache a un noyau peripherique en ortho ou au noyau central. L'acide pentaphenylbenzoique existe a l'etat de dimere forme par liaisons hydrogenes; toutefois, l'encombrement sterique des substituants ne permet pas la liaison directe des groupements carboxyliques qui sont plutot relies par un pont constitue de deux molecules de methanol. A l'etat solide, l'orientation des noyaux peripheriques dans les volumineux systemes [C.sub.6][Ph.sub.5]X est tres sensible a la taille des substituants'X',de sorte que l'angle de torsion du noyau en para repond inversement a l'encombrement croissant de'X'qui repousse de plus en plus les noyaux en ortho hors du plan du noyau central. Une discussion de l'interet de ces observations en ce qui concerne le mouvement correle dans les helices moleculaires, et en bout de ligne les machines moleculaires, est offerte. [Traduit par la Redaction] Mots-cles: polyarylbenzenes, orientation des substituants, barrieres de rotation, rotations correlees, complexes areniques du chrome., Introduction Polyarylbenzene derivatives have been intensively studied in recent years because of their applications in conducting polymers, (1) UV organic lasers, (2) and nonlinear optical devices and field effect transistors. [...]

Convenient and high-yielding syntheses of two new morpholine-substituted N-heterocyclic carbene ligands, 1-Ar-3-{2-(4-morpholinyl)phenyl}imidazolidin-2-ylidene (Ar = Dipp, Mes), are described. An investigation of corresponding palladium complexes reveals hemilability, and examples of both monodentate and bidentate coordination are observed. A preliminary investigation of the activity of these palladium complexes for Buchwald-Hartwig amination catalysis is presented. Key words: N-heterocyclic carbene, palladium, Buchwald-Hartwig amination, ligand design, hemilabile. On decrit les syntheses commodes et a haut rendement de deux nouveaux ligands carbene N-heterocyclique substitues par la morpholine, 1-Ar-3-{2-(4-morpholinyl)phenyl}imidazolidin-2-ylidene (Ar = Dipp, Mes). Une etude des complexes de palladium correspondants revele une hemilabilite et l'on observe des exemples de coordination monodente ainsi que bidente. On presente une etude preliminaire de l'activite de ces complexes de palladium pour la catalyse de la reaction d'amination de Buchwald-Hartwig. [Traduit par la Redaction] Mots-cles: carbene N-heterocyclique, palladium, amination de Buchwald-Hartwig, conception de ligands, hemilabile., Introduction The combination of a strong and weak donor within a bidentate ligand set can lead to interesting reactivity in the derived metal complexes, owing to the electronic asymmetry and [...]

The phosphino-phenolate complex ([κ.sup.2]-{2-i-[Pr.sub.2]P[C.sub.6] [H.sub.4]}O)Ir(COD) (COD = [η.sup.4]-1,5-cyclooctadiene; 1) is shown to be an effective precatalyst for the intramolecular hydroamination of unactivated alkenes with pendant secondary alkylamines, providing either pyrrolidine or piperidine heterocycles in high isolated yields. While monitoring the progress of a selected test reaction of this type, a significant induction period (~3 h) was observed; variable-temperature ¹H and [sup.31]P NMR studies (25-100°C) under catalytically relevant conditions revealed no new metal-containing species. In an effort to develop an enantiopure variant of 1, a synthetic route to the chiral ([κ.sup.2]-P,O)Ir(COD) complex (7), which features a 1-aryl- 2,5-dialkylphospholane structure derived from (2S,5S)-2,5-hexanediol cyclic sulfate, was developed. The structure of 7 was confirmed by use of single-crystal X-ray diffraction techniques. While 7 failed to provide enantioselectivity in the intramolecular hydroamination of unactivated alkenes with pendant secondary alkylamines, the activity of 7 was found to be comparable to that of 1. Key words: catalysis, hydroamination, iridium, ligand design. On montre que le complexe phosphino-phenolate, ([κ.sup.2]-{2-i[Pr.sub.2]P[C.sub.6][H.sub.4]}O)Ir(COD) (1), est un precatalyseur efficace pour l'hydroamination intramoleculaire d'alcenes non actives portant des chaines laterales avec des alkylamines secondaires qui conduit a la formation d'heterocycles pyrrolidine ou piperidine avec des rendements eleves en produits isoles. En observant le progres d'une reaction de ce type choisie comme representative, on a observe une periode d'induction significative (environ 3 heures); des etudes de RMN du ¹H et du [sup.31]P a temperature variable (25 a 100°C), dans des conditions catalytiquement appropriees ont revele qu'il n'y a pas de nouvelles especes contenant un metal. Dans un effort pour developper une variete enantiomeriquement pure du compose 1, on a mis au point une voie de synthese du complexe chiral ([κ.sup.2]-P,O)Ir(COD), 7, qui inclut une structure 1-aryl-2,5-dialkylphospholane obtenue a partir du sulfate cyclique du (2S,5S)-hexane-2,5-diol. La structure du compose 7 a ete confirmee par des techniques de diffraction des rayons X par un cristal unique. Meme si le compose 7 n'a pas permis d'obtenir d'enantioselectivite dans l'hydroamination intramoleculaire d'alcenes non actives portant des chaines laterales avec des alkylamines secondaires, l'activite de ce produit est comparable a celle du produit 1. Mots-cles : Catalyse, hydroamination, iridium, developpement d'un ligand., Introduction The prevalence of nitrogen-containing moieties in both naturally occurring and biologically active molecules has prompted the development of efficient methods for the formation of C-N bonds, including the use [...]

Lithiation of 7-azaindole, followed by quenching with [(R)-(1,1'-binaphthalene-2,2'-diyl)]chlorophosphite afforded the new chiral phosphoramidite 1 in 92% isolated yield. Treatment of 0.5 equiv. of [[(COD)MCl].sub.2] (M = Rh, Ir; COD = [η.sup.4]-1,5-cyclooctadiene) with 2 equiv. of 1 afforded the corresponding [([κ.sup.1]-P,N-1)([κ.sup.2]-P,N-1)MCl] complexes in 68% (2a, Rh) and 72% (2b, Ir) yield, while treatment of [(P[Ph.sub.3]).sub.3]RhCl with 1 equiv. of 1 afforded [(P[Ph.sub.3])([κ.sup.2]-P,N-1)RhCl] (3) as an analytically pure solid in 74% isolated yield. In examining the reaction of 1 with a mixture of 0.5 equiv. of [[(COD)RhCl].sub.2] and 1 equiv. of AgB[F.sub.4], an inseparable mixture of [[[([κ.sup.2]-P,N-1).sub.2]Rh].sup.+]B[F.sub.4.sup.-] (4a) and [[(COD)([κ.sup.2]-P,N-1)Rh].sup.+]B[F.sub.4.sup.-] (5a) was generated. Under analogous conditions employing [[(COD)IrCl].sub.2], the complex [[(COD)([κ.sup.2]-P,N-1)Ir].sup.+]B[F.sub.4.sup.-] (5b) was obtained in 86% isolated yield. Treatment of 0.5 equiv. of [[([η.sup.3]-allyl)PdCl].sub.2] with 1 afforded [[([η.sup.3]-allyl)([κ.sup.2]-P,N-1)Pd].sup.+][Cl.sup.-] (6) in 86% isolated yield. The application of 1 in platinum group metal-mediated asymmetric chemical transformations, including alkene hydrogenation and hydroboration, ketone hydrosilylation, and allylic alkylation, was examined. Key words: chiral, ligand, phosphoramidite, asymmetric catalysis. La lithiation du 7-azaindole, suivie d'un piegeage avec du chlorophosphite de [(R)-(1,1'-binaphtalene-2,2'diyle) conduit a la formation du nouveau phospharamidite chiral, 1, avec un rendement de 92% en produit isole. Le traitement de 0,5 equiv. de [[(COD)MCl].sub.2] (M= Rh, Ir; COD = [η.sup.4]-cycloocta-1,5-diene) avec deux equiv. de 1 conduit a la formation des complexes correspondants [[κ.sup.1]-P,N-1)([κ.sup.2]-P,N-1)MCl avec des rendements de 68% (2a, Rh) et de 72% (2b, Ir) alors que le traitement de [(P[Ph.sub.3]).sub.3] RhCl avec 1 equiv. de 1 conduit a la formation du [(P[Ph.sub.3])([κ.sup.2]-P,N-1)(RhCl] (3) qui a ete isole avec un rendement de 74% sous la forme d'un solide analytiquement pur. La reaction du produit 1 avec un melange de 0,5 equiv. de [[(COD)RhCl].sub.2] et un equiv. de AgB[F.sub.4] conduit a un melange inextricable de [[([κ.sup.2]-P,N-1).sub.2]Rh].sup.+]B[F.sub.4.sup.-] et de [[(COD)([κ.sup.2]-P,N-1)Rh].sup.+]B[F.sub.4.sup.-] (5a); dans des conditions impliquant l'utilisation du [[(COD) IrCl].sub.2], on obtient le complexe [[(COD)([κ.sup.2]-P,N-1)Ir].sup.+]B[F.sub.4.sup.-] (5b) avec un rendement isole de 86%. Le traitement de 0,5 equiv. de [[([η.sup.3]-allyl)PdCl].sub.2] avec le produit 1 conduit a la formation du produit [[([η.sup.3]-allyl) ([κ.sup.2]-P,N-1)Pd].sup.+][Cl.sup.-] (6) avec un rendement d 86% en produit isole. On a examine l'application du compose 1 dans les transformations chimiques asymetriques catalysees par un metal du groupe du platine, y compris les reactions d'hydrogenation et d'hydroboration des alcenes, d'hydrosilylation de cetones et d'alkylation allylique. Mots-cles: chiral, ligand, phosphoramidite, catalyse asymetrique., Introduction Transition metal-catalyzed asymmetric synthesis represents one of the most effective approaches for the preparation of chiral non-racemic molecules on both benchtop and industrial scales (1). Platinum-group metal (PGM) complexes [...]

The synthesis of the phosphine sulfide derivative of 1-[P.sub.i][Pr.sub.2-]indene, the use of this ligand in the preparation of neutral [[k.sup.2]-C,S] and cationic [[k.sup.2-H,S] Rh and Ir coordination complexes and the application of these complexes as catalysts for the addition of triethylsilane to styrene are reported. The observations reveal that species as well as monoanionic derivatives differ considerably in their coordination chemistry.

Treatment of trichlorovinylsilane with 3,3,4,4,5,5,6,6,7,7,8,8, 8-tridecafluoro-l-octanol (3 equiv.) in the presence of excess triethylamine produces the fluorous vinylsilane, 1, which can be isolated in 74% yield as an analytically pure oil. The addition of bis(pentafluorophenyl)borane to 1 produces the fluorous boranes, 2a-2b, as an analytically pure, isomeric mixture of anti-Markovnikov and Markovnikov hydroboration products in 38% isolated yield. Compounds 2a-2b are soluble in both arene solvents and perfluoro (methylcyclohexane). Treatment of 2a-2b with excess trimethylphosphine generates a mixture of products, including the Lewis adduct, 3, which can be isolated as an analytically pure oil in 15% yield. When exposed to either dimethylaminopyridine or piperidine at room temperature, the trimethylphosphine donor in 3 is cleanly displaced, based on in situ [sup.31]p NMR studies; under similar conditions, triethylamine does not react with 3. Addition of either dimethylaminopyridine or piperidine to 2a-2b, followed by purification and subsequent treatment with an excess of either hydrogen chloride or p-toluenesulfonic acid, results in cleavage of the Si-O linkages and the regeneration of 3,3,4, 4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol. Key words: fluorous, borane, silane, Lewis acid.

Reactions involving Fe[(NO).sub.2][(CO).sub.2] and the bis(phosphine) ligands bis(diphenylphosphino)methane (DPPM), bis(diphenylphosphino)acetylene (DPPA), 1,6-bis(diphenylphosphino)hexane (DPPH), and 1,4-bis(diphenylphosphino)benzene (DPPB) have been examined. From these reactions, the mononuclear complex, Fe([K.sup.1]-DPPM)[(NO).sub.2](CO) 3, linear dinuclear species of the type [Fe.sub.2]([mu]-L)[(NO).sub.4][(CO).sub.2] (L = [Ph.sub.2]PC[H.sub.2]PP[h.sub.2] 4, [Ph.sub.2]PC[equivalent to] CPP[h.sub.2] 5, [Ph.sub.2]PC[H.sub.2][(CH[sub.3].sub 4)]C[H.sub.2]PP[h.sub.2] 6, and P[h.sub.2]P(p-Csub.6][H.sub.4])PP h.sub.2] 7), and macrocyclic dinuclear species of the type [Fe.sub.2][([mu]-L).sub.2][(NO).sub.4] (L = P[h.sub.2]PC[H.sub.2]PP[H.sub.2] 8 and P[h.sub.2]PC[equivalent to]CPP[h.sub.2] 9) were isolated and spectroscopically characterized. For 4, 5, 8, and 9, the solid-state molecular structures of the products were determined by use of single-crystal X-ray diffraction techniques. Key words: dinitrosyliron, iron nitrosyls, dinuclear macrocycles, bis(phosphine) complexes.

Research discusses the chemical shift dispersons involved in the reactions between pentafluorophenyllithium with the cyclopentadienones and analyzing it using variable-temperature (sup)19F NMR spectroscopy to understand the molecular dynamics of cyclopentadienones.

The first nickel-catalyzed N -arylation of amides with (hetero)aryl (pseudo)halides employing an organic amine base is described. By using a bis(cyclooctadienyl)nickel/8-[2-(dicyclohexylphosphinyl)phenyl]-1,3,5,7-tetramethyl-2,4,6-trioxa-8-phosphaadamantane catalyst mixture in combination with DBU/NaTFA as a dual-base system, a diversity of (hetero)aryl chloride, bromide, tosylate, and mesylate electrophiles were successfully cross-coupled with structurally diverse primary amides, as well as a selection of secondary amide, lac-tam, and oxazolidone nucleophiles. [ABSTRACT FROM AUTHOR]

Research was conducted to isolate and characterize cyclopenta[l]phenanthrene (dibenz[e,g]indene) with isodibenzindene using x-ray crystallography and nuclear magnetic resonance spectroscopy. This compound is trapped in situ by its precursor cyclopenta[l]phenanthrene. Results using the Diels-Alder dimerization confirm RHF/3-21G calculations regarding the relative stability of the isoindene.