Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• in the er. Pd(acac)2 and Pd(MeCN)2(OTs)2 were also tested without significant improvements. Despite the fact that palladium acetate slightly better performed as shown in Table 1, we decided to continue with palladium trifluoroacetate due to its higher reactivity in forming palladium complexes with N

Synthesis of 7-azabicyclo[4.3.1]decane ring systems from tricarbonyl(tropone)iron via intramolecular Heck reactions

• Aaron H. Shoemaker,
• Elizabeth A. Foker,
• Elena P. Uttaro,
• Sarah K. Beitel and
• Daniel R. Griffith

Beilstein J. Org. Chem. 2023, 19, 1615–1619, doi:10.3762/bjoc.19.118

• cleanly according to TLC analysis, but the isolated yield of the intramolecular Heck product was low, perhaps due to instability of one of the intermediate palladium complexes and/or a slow olefin insertion step. Moreover, the product was obtained as an inseparable mixture of the allylic carbamate 18 and

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• strategies for C–N bond formation have been extensively explored by various research groups for the N-arylation of amines. Specifically, seminal contributions by Buchwald [15] and Hartwig [16] involving the use of palladium complexes as catalysts in the presence of either phosphine or diamine ligands for C–N

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• –4.23 for the L1-Pd complex. In addition, the 1H and 13C NMR spectra of nickel(II) complexes (L1-Ni, L2-Ni, and L3-Ni) show clear and simple signals of protons and carbons. However, the palladium complexes derived from ligands L1 and L2 exhibited major and minor sets of signals in both NMR experiments

• . This could be attributed to the distorted square planar geometry of the palladium complexes [23][24][25][26], compared to the square planar structure of the analogous nickel(II) chelates [15][27]. In fact, the sets of the signals were reduced upon warming the NMR probe. Next, these freshly prepared

• conformations analyzed by the 1H NMR spectra of nickel and palladium complexes, presumably correlated with their activity. According to the previous activities of derivatives of this nature [15][16] the cis-complex was identified as the therapeutic arrow. We initially tried to determine the driving force

A visible-light-induced, metal-free bis-arylation of 2,5-dichlorobenzoquinone

• Pieterjan Winant and
• Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 2315–2320, doi:10.3762/bjoc.17.149

• multistep procedures requiring large amounts of toxic metal complexes [12][33][34]. Later improvements still demand prefunctionalization of the quinone substrate [35][36][37]. While effectively eliminating this requirement, CH bis-arylation using palladium complexes still suffers from regioselectivity

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

A chiral self-sorting photoresponsive coordination cage based on overcrowded alkenes

• Constantin Stuckhardt,
• Diederik Roke,
• Wojciech Danowski,
• Edwin Otten,
• Sander J. Wezenberg and
• Ben L. Feringa

Beilstein J. Org. Chem. 2019, 15, 2767–2773, doi:10.3762/bjoc.15.268

• supramolecular palladium complexes caused immediate crystallization [22]. Moreover, azobenzenes have been used to functionalize both the interior [23] and exterior [24] of SCCs to photochemically control guest binding and release. Furthermore, incorporation of dithienylethene into the ligands connecting the

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• different catalysts, such as palladium, copper, silver, iron, nickel, ruthenium, cobalt, etc. Palladium catalysis Palladium is a member of the nickel triad in the periodic table, and palladium complexes exist in three oxidation states, Pd(0), Pd(II), and Pd(IV). Straightforward interconversion between

• a prevalent catalyst in a huge number of organic transformations. Similar to palladium complexes, copper complexes generally exist in four oxidation states, Cu(0), Cu(I), Cu(II), and Cu(III) and various fluorination reactions could be developed by different catalytic mechanisms. Fluorination of

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

• Piotr Pomarański,
• Piotr Roszkowski,
• Jan K. Maurin,
• Armand Budzianowski and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

• acid) in order to visualize the presence of individual enantiomers (see Supporting Information File 1 for details). Based on the current knowledge on the chemistry of palladium complexes with SPhos [42][43][44] we proposed a sequence in the arylation process and the substitution mechanism for the

D-Fructose-based spiro-fused PHOX ligands: synthesis and application in enantioselective allylic alkylation

• Michael R. Imrich,
• Jochen Kraft,
• Cäcilia Maichle-Mössmer and
• Thomas Ziegler

Beilstein J. Org. Chem. 2018, 14, 2082–2089, doi:10.3762/bjoc.14.182

• -glucosamine and the sugar was linked to the aromatic system via an annulated oxazoline. Palladium complexes of 2 were used in allylic substitution of allyl acetates with dimethyl malonate as nucleophile and ee values from 69% to 98% were obtained [19]. Recently, we presented the synthesis of carbohydrate

• ligands like Kunz’ PHOX ligand 2 or our PyOx ligands 3 and 4 [14][19][20][21][22][52][53]. Palladium complexes of both ligands 5b and 5i were suitable to catalyze the allylic substitution in an enantioselective manner (Table 3). Conversions were quantitative or at least high with both ligands in a number

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• enantioselectivities (up to 94% ee) by using chiral nickel and palladium complexes with imidazoline and pyridine-oxazoline ligands while the first additions of enaminones to isatin imines catalyzed by chiral phosphoric acids provided even higher enantioselectivities (up to 97% ee). In spite of these significant

Highly bulky and stable geometry-constrained iminopyridines: Synthesis, structure and application in Pd-catalyzed Suzuki coupling of aryl chlorides

• Yi Lai,
• Zhijian Zong,
• Yujie Tang,
• Weimin Mo,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen,
• Liqun Jin,
• Wen-hua Sun and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 213–221, doi:10.3762/bjoc.13.24

• wide variety of different substituents were introduced leading to a diversity with regard to steric and electronic aspects [54][55][56][57][58][59]. Recently, we have developed a series of geometry-constrained iminopyridyl compounds [60][61][62][63][64] and their corresponding palladium complexes

• analyses are in good agreement with that of the previously reported palladium complexes [72]. All of these complexes could be stored open to air without any decomposition for several months except Pd4. Their melting points [>240 °C] indicated their high thermostability, especially Pd2 with a melting point

• up to 325 °C. With these sterically hindered iminopyridine–palladium complexes Pd1 to Pd5 in hand, we firstly investigated their catalytic activity directly in Suzuki cross-coupling reactions with chlorobenzene as the electrophile. The reactions were performed under the previously reported conditions

Cp₂TiCl/D₂O/Mn, a formidable reagent for the deuteration of organic compounds

• Antonio Rosales and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2016, 12, 1585–1589, doi:10.3762/bjoc.12.154

• complexes catalyse α-deuteration of amines and alcohols [13] and palladium complexes catalyse the ortho-selective deuteration of arenes [14]. Also, SmI2/D2O-mediated the chemoselective synthesis of α,α-dideuterio alcohols directly from carboxylic acid under single-electron-transfer conditions [15]. However

A T-shape diphosphinoborane palladium(0) complex

• Patrick Steinhoff and
• Michael E. Tauchert

Beilstein J. Org. Chem. 2016, 12, 1573–1576, doi:10.3762/bjoc.12.152

• complexes only few examples featuring a η1-type Pd→B interaction have been reported [6][7]. However, these complexes require phosphines or pyridines as a stabilizing co-ligand, which can act as an inhibitor in catalytic transformations [7]. Similarly, monometallic 14 VE palladium complexes featuring a

• complex 9 the trans-coordinated palladium center featured an obtuse P1–Pd1–P2 angle of 157.72(2)°. Conclusion In conclusion we synthesized the zerovalent palladium complex [{(o-PCy2-C6H4)2BPh}Pd(0)] 9. Complex 9 supplements the few known examples (e.g., 6 [11]) of 14 VE palladium complexes bearing a

• (e.g., 1 [6] and 2 [7]), or as a boron containing π-ligand adopting η2-B,C (3) [8] or η3-B,C,C coordination (4 and 5) [5][9][10]. Changes of the hapticity appear to have significant influence onto the reactivity of the coordinated transition metal towards substrates [8]. For zerovalent palladium

Methylpalladium complexes with pyrimidine-functionalized N-heterocyclic carbene ligands

• Dirk Meyer and
• Thomas Strassner

Beilstein J. Org. Chem. 2016, 12, 1557–1565, doi:10.3762/bjoc.12.150

• complexes were fully characterized by standard methods and in three cases also by a solid state structure. Keywords: alkane activation; alkyl complex; NHC; palladium; solid state structure; Introduction Palladium complexes have been shown to be versatile homogeneous catalysts in a variety of reactions [1

• ]. One of the most prominent examples are the palladium catalyzed cross-coupling reactions [2], but in addition palladium complexes recently received much attention also in the field of selective CH oxidations [3][4][5][6]. The catalytic conversion of alkanes and especially of methane into a value-added

• “Catalytica” bispyrimidine system, for the biscarbene system the palladium complexes turned out to be more stable than the corresponding platinum complexes under the reaction conditions [31][32], although Peter Hofmann had recently shown the stability and reactivity of the platinum-alkyl complexes with bis

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• their Lewis acidity. Cationic palladium complexes [123], in particular, possess a wide breadth of reactivity, having been used to catalyze Diels–Alder [124][125], aldol and Mannich reactions [126][127][128], Wacker oxidations [129], polymerizations of alkenes [130][131], and asymmetric 1,4-additions

• ], those catalyzed by cationic palladium have been much less thoroughly examined. We hypothesized that our catalytic cycles for the Fujiwara–Moritani, arylboronic acid, and aryl iodide coupling reactions catalyzed by cationic palladium complexes are composed of three key steps; (1) aromatic C–H activation

• have provided insight into the roles of additives HBF4, BQ, and AgOAc, as well as the crucial steps of each reaction’s catalytic cycle. Lastly, this study highlights the advantages of dicationic palladium complexes in synthesis, and their tolerance to aqueous media. Such cationic reagent/medium

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

• and platinum complexes containing 1,2,3-triazole-tethered NHC ligands. The obtained palladium complexes displayed high activity in aqueous Suzuki–Miyaura cross-coupling reactions. We are interested in the synthesis and use of functionalized NHC ligands [20][28][29][30][31]. Herein, the synthesis

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

• crystals of [2a-PdCl2] and [5-Pd(2-Me-allyl)]OTf suitable for X-ray diffraction analysis (Figure 6). For an overview of metric parameters of all palladium complexes see Table 3. The solid-state structures of [2a-PdCl2] (Figure 6, left) and its cationic congener [2a-PdCl]2(BF4)2 (Figure 5) show distinct

• %. Molecular structures of [2a-Cp*IrI]+ (left) and [5-Cp*IrI]+ (right). Anisotropic displacement ellipsoids set at the 50% probability level. Hydrogen atoms have been omitted for clarity. For selected bond lengths and angles see Table 2. Formation of palladium complexes of ligands 2a, 5 and 7. (A) Formation of

Spiro-fused carbohydrate oxazoline ligands: Synthesis and application as enantio-discrimination agents in asymmetric allylic alkylation

• Jochen Kraft,
• Martin Golkowski and
• Thomas Ziegler

Beilstein J. Org. Chem. 2016, 12, 166–171, doi:10.3762/bjoc.12.18

• for metal-catalyzed asymmetric syntheses [16] we recently described the preparation of spiro-fused oxazoline ligands of type C from D-fructose [17]. We could demonstrate that our oxazoline ligands, in contrast to A, were able to form air and moisture-stable palladium complexes of type D upon reaction

• of the palladium complexes can be distinguished. It is also reasonable to assume that exo/endo isomers 15 and 17 undergo fast allyl rotation via a η3–η1–η3 isomerization mechanism and thus, exist in a dynamic equilibrium which is approximately ten to hundred times faster than alkylation [7

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• %). The oxazolines were prepared from enantiomerically pure α-aminoalcohols. The structures of the synthesized palladium complexes were confirmed by NMR, FTIR, TOFMS, UV–visible spectroscopic analysis and X–ray diffraction. The optical properties of the complexes were evaluated by the determination of the

• determined. Keywords: aminoalcohols; catalysis; dye decolorization; optical properties; oxazolines; palladium complexes; Introduction Palladium complexes have been used as starting materials to prepare polymers [1], agrochemicals [2], pharmaceuticals [3], flavors and fragrances [4]. They have also been

• and efficiencies to treat colored waters [20][21][22]. Owing to the easy formation of palladium–oxazoline complexes, it was very interesting to investigate the ability of some synthetic dyes to coordinate to palladium complexes by developing binary systems. This was done by complexing oxazoline with

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

• halides were used as oxidants. Ruthenium, iridium, and palladium complexes acted as catalysts. In most cases, structurally simple alcohols, which are taken in a large excess relative to the CH-reagent, served as OH-reagents. The exception is a study [95], in which the coupling was accomplished using an

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

• develop a stable and efficient Pd catalyst for these reactions. Recently, palladium complexes containing imidazole-imines [12], binary nanoclusters [13], N-heterocyclic carbenes (NHCs) [14], nanoparticles [15], palladacycles [16], and Schiff bases [17] have been developed as highly effective phosphine

Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

• Matthieu Jouffroy,
• Rafael Gramage-Doria,
• David Sémeril,
• Dominique Armspach,
• Dominique Matt,
• Werner Oberhauser and
• Loïc Toupet

Beilstein J. Org. Chem. 2014, 10, 2388–2405, doi:10.3762/bjoc.10.249

• coordinated water molecule appeared as a broad singlet at δ = 5.64 ppm in the 1H NMR spectrum recorded at −80 °C [45]. This chemical shift value is typical for aqua palladium complexes [49][50][51]. A single crystal X-ray diffraction study (Figure 2) confirmed the coordination of a {PdCl2(H2O)} fragment

Rational design of cyclopropane-based chiral PHOX ligands for intermolecular asymmetric Heck reaction

• Marina Rubina,
• William M. Sherrill,
• Alexey Yu. Barkov and
• Michael Rubin

Beilstein J. Org. Chem. 2014, 10, 1536–1548, doi:10.3762/bjoc.10.158

• ; Introduction The asymmetric Heck reaction is one of the most powerful and versatile processes for the enantioselective construction of new carbon–carbon bonds. Intramolecular versions of this reaction catalysed by palladium complexes with BINAP and related diphosphine ligands [1][2] allow for efficient

Self-assembly of metallosupramolecular rhombi from chiral concave 9,9’-spirobifluorene-derived bis(pyridine) ligands

• Rainer Hovorka,
• Sophie Hytteballe,
• Torsten Piehler,
• Georg Meyer-Eppler,
• Filip Topić,
• Kari Rissanen,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 432–441, doi:10.3762/bjoc.10.40

• compared to the ratios obtained by other techniques, e.g. NMR spectroscopy, as we have recently reported [28]. Finally, we were able to grow single crystals of the dinuclear palladium complexes derived from the racemic ligands from a 3:1 mixture of dichloromethane and acetonitrile using ethyl acetate as