Ring-whizzing in polyene-PtL₂ complexes revisited

• Oluwakemi A. Oloba-Whenu,
• Thomas A. Albright and
• Chirine Soubra-Ghaoui

Beilstein J. Org. Chem. 2016, 12, 1410–1420, doi:10.3762/bjoc.12.135

• ; density functional theory (DFT); hapototropic rearrangements; HOMO–LUMO interactions; polyene-ML2 complexes; ring-whizzing; Introduction Polyene–transition metal complexes were found to undergo fluxional rearrangements as early as 1956 with the preparation of Cp2Fe(CO)2 [1]. The migration of an MLn unit

Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

• Shaojin Gu,
• Jiehao Du,
• Jingjing Huang,
• Huan Xia,
• Ling Yang,
• Weilin Xu and
• Chunxin Lu

Beilstein J. Org. Chem. 2016, 12, 863–873, doi:10.3762/bjoc.12.85

• [1][2][3][4][5][6][7][8][9][10][11][12]. A number of transition metal complexes of NHCs containing pyridine [13], pyrimidine [14], pyrazole [15][16], naphthyridine [17], pyridazine [18], and phenanthroline [19][20] donating groups have been studied in metal-catalyzed organic transformations. Recently

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

• Vladislav Vasilenko,
• Torsten Roth,
• Clemens K. Blasius,
• Sebastian N. Intorp,
• Hubert Wadepohl and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83

• have a significant influence on the binding geometry und coordination properties of these bidentate P,N-donors. Keywords: P,N-ligands; phosphanylformamidines; phosphine imines; transition metal complexes; Introduction P,N-ligands have been applied in a wide variety of chemical reactions ranging from

• folded, whereas complexes of L3 exhibit a strong deviation from planarity. In summary, these results may be utilized for the design, preparation and structural elucidation of novel late transition metal complexes. Investigations into their potential as precatalysts for organic transformations are

Scope and limitations of the dual-gold-catalysed hydrophenoxylation of alkynes

• Adrián Gómez-Suárez,
• Yoshihiro Oonishi,
• Anthony R. Martin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2016, 12, 172–178, doi:10.3762/bjoc.12.19

• metal and main-group chemistry [10][11][12][13]. We have been interested in exploring the use of NHC ligands in transition metal complexes for the development of highly active and well-defined catalysts. One of our main interests during the last decade has been to study the use of gold–NHC species as

Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 117–124, doi:10.3762/bjoc.12.13

• bond [7][8], which favored the synthesis of new NHCs and to their use as ligands in transition metal complexes. The latter complexes were usually obtained by an easy replacement of a phosphine by the new NHC ligand, displaying a very high stability under many catalytic conditions. Furthermore, NHCs

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• as prepared by controlled living ring-opening metathesis polymerization (ROMP) of the respective metal-incorporating monomers. Ferrocene- and other metallocene-modified polymers, macromolecules including metal-carbonyl complexes, polymers tethering early or late transition metal complexes, etc. are

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

• Nicolas Desbois,
• Sandrine Pacquelet,
• Adrien Dubois,
• Clément Michelin and
• Claude P. Gros

Beilstein J. Org. Chem. 2015, 11, 2202–2208, doi:10.3762/bjoc.11.239

• forming highly stable transition metal complexes making them efficient delivery vehicles for radioisotopes. The radioactive 64Cu2+-porphyrin is known to be extremely stable. Shi et al. [19] have described an easy and efficient radiolabeling of the porphyrin macroring with 64Cu. Mukai et al. [20] have

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• carbenes (NHCs) have been recognized as a class of strong donating ligands which can stabilize various metal complexes of catalytic importance. Transition metal complexes bearing NHCs are more stable to air, moisture, heat, and tolerant toward oxidation compared to phosphine ligands [1][2][3][4][5][6][7

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• , uncommon reaction sequences. Homogeneous PRCs form one class that encompasses soluble organic dyes [1] as well as transition metal complexes; particularly those of Ru and Ir. Study of the latter markedly escalated from 2008 thanks to papers from the groups of MacMillan [2], Yoon [3] and Stephenson [4]. The

Ruthenium indenylidene “1^st generation” olefin metathesis catalysts containing triisopropyl phosphite

• Stefano Guidone,
• Fady Nahra,
• Alexandra M. Z. Slawin and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2015, 11, 1520–1527, doi:10.3762/bjoc.11.166

• shorten or provide alternative synthetic pathways for the synthesis of natural products displaying complex chemical structures [5][6][7][8][9]. Ru-based pre-catalysts are known to be more air-, moisture- and functional-group tolerant compared to early transition metal complexes [10][11][12][13]. In

A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells

• Gleb Sorohhov,
• Chenyi Yi,
• Michael Grätzel,
• Silvio Decurtins and
• Shi-Xia Liu

Beilstein J. Org. Chem. 2015, 11, 1052–1059, doi:10.3762/bjoc.11.118

• ]. Although devices with the most commonly used dyes based on polypyridyl transition-metal complexes show excellent photovoltaic performances with high power conversion efficiencies of over 11% [4], metal-free organic dyes have significant advantages in several aspects. These comprise for example large molar

Mechanical stability of bivalent transition metal complexes analyzed by single-molecule force spectroscopy

• Manuel Gensler,
• Christian Eidamshaus,
• Maurice Taszarek,
• Hans-Ulrich Reissig and
• Jürgen P. Rabe

Beilstein J. Org. Chem. 2015, 11, 817–827, doi:10.3762/bjoc.11.91

TTFs nonsymmetrically fused with alkylthiophenic moieties

• Rafaela A. L. Silva,
• Bruno J. C. Vieira,
• Marta M. Andrade,
• Isabel C. Santos,
• Sandra Rabaça,
• Dulce Belo and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 628–637, doi:10.3762/bjoc.11.71

• derivatives have been reported in the last 40 years and many have been at the basis of several conducting, superconducting and other important electronic materials [2][3][4][5][6]. Bisdithiolene–transition metal complexes with square planar structures can be seen as inorganic TTF analogues, in which a

• transition metal replaces the central double bond. They have similar frontier orbitals to TTF and have been also at the basis of several electronic materials [7]. An additional connection between the TTF derivatives and the bisdithiolene–transition metal complexes was recently provided by complexes with

• converted to transition metal complexes based on extended thiophene/TTF-fused dithiolene ligands. They were obtained by cross-coupling reactions between alkylated thio and oxo compounds. The incorporation of these alkyl groups in the thiophenic ring is expected to increase the solubility of these TTFs and

Photocatalytic nucleophilic addition of alcohols to styrenes in Markovnikov and anti-Markovnikov orientation

• Martin Weiser,
• Sergej Hermann,
• Alexander Penner and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2015, 11, 568–575, doi:10.3762/bjoc.11.62

• light sources, the research field of photoredox catalysis has tremendously grown over the past decade [1][2][3][4][5][6][7]. Transition metal complexes, mainly [Ru(bpy)3]2+ [7], were most often used as photocatalysts, whereas the potential of organic compounds and dyes has not yet been fully exploited

• their potential and versatile applicability in chemical syntheses. Their non-photochemical counterparts require acids, bases or transition metal complexes as catalysts [10]. The first examples of photochemical olefin aminations were reported by Cookson et al. [11] and Kawanisi et al. [12] in the 1960s

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• the hydrogen transfer catalyzed by transition metal complexes. In these reactions, compounds with a double bond or a C–Hal bond act as oxidants (hydrogen acceptors). Examples of these reactions with aldehydes or primary alcohols as C–H reagents are given in Table 2. Crotononitrile, acetone, and benzyl

An improved procedure for the preparation of Ru(bpz)₃(PF₆)₂ via a high-yielding synthesis of 2,2’-bipyrazine

• Danielle M. Schultz,
• James W. Sawicki and
• Tehshik P. Yoon

Beilstein J. Org. Chem. 2015, 11, 61–65, doi:10.3762/bjoc.11.9

• couplings [13][14], and photooxygenation reactions [15][16]. Similarly, Zheng has reported oxidatively initiated indole synthesis [17] and [3 + 2] cycloaddition [18][19] reactions using photocatalyst 2. Finally, a variety of transition metal complexes bearing bipyrazyl ligands have been prepared and

• of bpz. An improved synthesis of this ligand would be useful both in the context of the growing interest in photoredox catalysis as well as other organometallic and inorganic applications of bpz-supported transition metal complexes. Our optimization studies for the reductive coupling of 2

A novel 4-aminoantipyrine-Pd(II) complex catalyzes Suzuki–Miyaura cross-coupling reactions of aryl halides

• Claudia A. Contreras-Celedón,
• Darío Mendoza-Rayo,
• José A. Rincón-Medina and
• Luis Chacón-García

Beilstein J. Org. Chem. 2014, 10, 2821–2826, doi:10.3762/bjoc.10.299

• -free catalysts for SM coupling reactions. Transition metal complexes that have shown a wide range of biological activity are those containing the pyrazolone derivative 4-aminoantipyrine (4-amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one, or simply “4-AAP”) [18]. Pyrazoles, in general, are one of the

• complexes of 4-AAP have shown anti-inflammatory, analgesic, antiviral, antipyretic, antirheumatic and antimicrobial activity [20][21]. Despite the potential biological importance of 4-AAP, the catalytic activity of its transition metal complexes for C–C bond formation have not yet been investigated. Herein

• most important classes of bioactive heterocycles, having attracted increasing interest to the pharmaceutical, chemical and agricultural industries over the past decade, and in recent years a number of research articles have been published specifically about 4-AAP [19]. Analogues and transition metal

Homogeneous and heterogeneous photoredox-catalyzed hydroxymethylation of ketones and keto esters: catalyst screening, chemoselectivity and dilution effects

• Axel G. Griesbeck and
• Melissa Reckenthäler

Beilstein J. Org. Chem. 2014, 10, 1143–1150, doi:10.3762/bjoc.10.114

• visible region and appropriate redox activity in the excited states. Many potent photoredox catalysts with sufficient long-term stability are transition metal complexes with excited MLCT states that can be generated in the visible. Another important group of photocatalytic active compounds are

Organic synthesis using photoredox catalysis

• Axel G. Griesbeck

Beilstein J. Org. Chem. 2014, 10, 1097–1098, doi:10.3762/bjoc.10.107

• many cases appropriate sacrificial components. In recent years, three major groups of light-absorbing molecules/materials have been (re)investigated, which facilitate a wide range of redox activation from their excited states: transition metal complexes (e.g., the thoroughly investigated Ru(bipy)3 and

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• P-nucleophile or the C-electrophile. Chiral phosphines have attracted more and more interest since they are employed as ligands in transition metal complexes to perform asymmetric catalysis [117]. Enantiopure phosphines have mostly been prepared by starting from enantiopure products or by resolution

On the mechanism of photocatalytic reactions with eosin Y

• Michal Majek,
• Fabiana Filace and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2014, 10, 981–989, doi:10.3762/bjoc.10.97

• vast majority of photochemical reactions known until the 1980s exploited stoichiometric amounts of a photoactive molecular entity to drive a chemical transformation [1]. Only recently, a steadily growing number of homogeneous transition metal complexes which are redox-active and show absorption in the

Gold(I)-catalyzed enantioselective cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2013, 9, 2250–2264, doi:10.3762/bjoc.9.264

• , cycloadditions are atom economical, and usually take place with high levels of regio- and stereocontrol. Especially relevant in terms of synthetic practicality are cycloadditions which are catalyzed by transition metal complexes [19][20][21][22][23]. In particular, gold(I) complexes, owing to their high

Gold(I)-catalyzed 6-endo hydroxycyclization of 7-substituted-1,6-enynes

• Ana M. Sanjuán,
• Alberto Martínez,
• Patricia García-García,
• Manuel A. Fernández-Rodríguez and
• Roberto Sanz

Beilstein J. Org. Chem. 2013, 9, 2242–2249, doi:10.3762/bjoc.9.263

• and co-workers, as substrates in the identification of new reactivities catalyzed by gold and other transition metal complexes [5][6][7][8][9][10][11][12][13]. Cyclopropyl metal carbenes II are usually formed by exo-dig processes from enynes I bearing a terminal alkyne, which in the absence of

Synthesis of axially chiral gold complexes and their applications in asymmetric catalyses

• Yin-wei Sun,
• Qin Xu and
• Min Shi

Beilstein J. Org. Chem. 2013, 9, 2224–2232, doi:10.3762/bjoc.9.261

• intramolecular hydroamination of olefins has also been significantly improved by using various transition metal complexes or other metal complexes [69][70][71][72][73][74][75][76][77]. However, to the best of our knowledge, the enantioselective intramolecular hydroamination of olefins catalyzed by gold complexes

Synthesis, characterization and luminescence studies of gold(I)–NHC amide complexes

• Adrián Gómez-Suárez,
• David J. Nelson,
• David G. Thompson,
• David B. Cordes,
• Duncan Graham,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2013, 9, 2216–2223, doi:10.3762/bjoc.9.260

• catalysts in gold-catalyzed processes [1][2][3][4][5][6][7]. This has led several research groups to investigate general, green and straightforward methodologies for the synthesis of organogold complexes. We have focused on the synthesis and study of transition metal complexes bearing N-heterocyclic carbene