Palladium-catalyzed ortho-halogenations of acetanilides with N-halosuccinimides via direct sp² C–H bond activation in ball mills

• Zi Liu,
• Hui Xu and
• Guan-Wu Wang

Beilstein J. Org. Chem. 2018, 14, 430–435, doi:10.3762/bjoc.14.31

• ][24][25][26][27][28]. A few mechanochemical ortho-C–H bond activation reactions under the catalysis of rhodium and palladium salts have been reported [29][30][31][32][33][34][35][36][37][38]. Hernández and Bolm reported the rhodium-catalyzed bromination and iodination of 2-phenylpyridine using N

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• ). However, a full conversion of thioamide 1a in these experiments was not achieved in spite of the 1.2-fold excess of diazomalonate 2a used in the process. Further increasing the amount of diazomalonate 2a (up to 2.1 equiv) in the reaction with rhodium tetrapivalate resulted in the enhancement of the yield

• was established that the main products of diazoesters 2a,b,d in reactions with thioacetamides 1a–e, catalyzed by rhodium complexes, were sulfur-containing heterocycles, 5-amino-3-(alkoxycarbonylamino)thiophene-2-carboxylates 3, 2-(5-amino-2-methoxycarbonylthiophen-3-yl)aminomalonates 4 and (2-cyano-5

• evidence of high reactivity of rhodium complexes in these processes [54][55]. This literature data brought us to the suggestion that low reactivity of diazoesters 2 toward thioamides 1 in the presence of Rh(II)-catalysts is caused by binding the two latter chemicals to furnish the adducts of the type 6

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides

• Valentin A. Rassadin,
• Mirko Scholz,
• Anastasiia A. Klochkova,
• Armin de Meijere and
• Victor V. Sokolov

Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187

• latter transformation was a rhodium octanoate-catalyzed intramolecular carbenoid insertion into an ortho CAr–H bond (Scheme 1) [21][22], which proceeded with good yields in most cases. However, with non-equivalent aryl ortho-positions in the starting diazo compounds, mixtures of regioisomers – virtually

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• -workers have successfully demonstrated rhodium(III)-catalyzed C–H bond functionalization under mechanochemical conditions [182]. Advantageously, the developed method adopted mild reaction conditions, i.e., in solvent-free medium and at room temperature. It required a minimum amount of toxic metal salt of

• the metal catalyst from rhodium to iridium. In 2016, using an Ir(III) catalyst an unprecedented ortho-selective Csp2–H bond amidation of benzamides with sulfonyl azides as the amide source was done under solvent-free ball mill conditions (Scheme 51) [183]. They could also isolate cyclic iridium

• complex H in ball-milling conditions. In 2015, the Bolm group reported the synthesis of [Cp*RhCl2]2 under LAG from rhodium(III) chloride hydrate and pentamethylcyclopentadiene (Cp*H) at lesser reaction time than solution-based protocols. Subsequently, they utilized the [Cp*RhCl2]2 for the solvent-free

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

• Debasish Sengupta,
• Koushik Bhowmik,
• Goutam De and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

• first palladium-catalyzed arylation of thiols was reported by Migita and co-workers in 1980 [5], and soon after Cristau and co-workers developed a nickel-catalyzed route for C–S cross-coupling reactions [6]. Other metals such as copper [7], cobalt [8], iron [9], rhodium [10], manganese [11], indium [12

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

2-Methyl-2,4-pentanediol (MPD) boosts as detergent-substitute the performance of ß-barrel hybrid catalyst for phenylacetylene polymerization

• Julia Kinzel,
• Daniel F. Sauer,
• Marco Bocola,
• Marcus Arlt,
• Tayebeh Mirzaei Garakani,
• Andreas Thiel,
• Klaus Beckerle,
• Tino Polen,
• Jun Okuda and
• Ulrich Schwaneberg

Beilstein J. Org. Chem. 2017, 13, 1498–1506, doi:10.3762/bjoc.13.148

• rhodium-based biohybrid catalyst. Unlike commonly used detergents such as sodium dodecyl sulfate or polyethylene polyethyleneglycol, MPD does not form micelles in solution. Molecular dynamics simulations revealed the effect and position of stabilizing MPD molecules. The advantage of the amphiphilic MPD

• that FhuA ΔCVFtev is correctly folded even up to eight weeks. Coupling efficiency of the rhodium catalyst to FhuA ΔCVFtev is more than 90% The rhodium catalyst 1 bearing a maleimide group was attached to FhuA ΔCVFtev for the generation of the biohybrid catalyst [Rh]-FhuA ΔCVFtev 2 as previously

• of the cysteine function of 2 (Cys545) using the fluorescence dye ThioGlo® 1 (fluorescent thiol reagent, Figure S2, Supporting Information File 1). More than 90% of the cysteines are occupied, showing a very high coupling efficiency of the rhodium catalyst. Further, the biohybrid conjugate was

Unpredictable cycloisomerization of 1,11-dien-6-ynes by a common cobalt catalyst

• Abdusalom A. Suleymanov,
• Dmitry V. Vasilyev,
• Valentin V. Novikov,
• Yulia V. Nelyubina and
• Dmitry S. Perekalin

Beilstein J. Org. Chem. 2017, 13, 639–643, doi:10.3762/bjoc.13.62

• the diene compounds 3a,b in 90–95% yields. These compounds were also obtained using a 1,2-bis(diphenylphosphino)benzene (dppbz) ligand. Despite the extensive studies of enyne transformations, this type of cyclization has been achieved only recently, using a cyclobutadiene rhodium complex as a catalyst

• recently prepared by the rhodium-catalyzed cyclopropanation [44]. Compounds 4 and 5 were obtained as mixtures with approximately 1:1 ratio and total 80–90% yields. Numerous attempts to convert 5 into the more stable isomer 4 using strong bases or transition metal catalysts were unsuccessful. The cobalt

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• 55 via a formal 1,4-addition of arylboronic acids to β-aryl-α,β-unsaturated ketones and esters [39]. Thus, the α,β-unsaturated diester 52 was coupled with arylboronic acid in the presence of rhodium(I)/Chiraphos® complex as a catalyst to obtain derivative 53, which next underwent a Claisen

• byproducts (Scheme 32). Chiral 3-aryl-1-indanones 107 have been synthesized via rhodium-catalyzed asymmetric cyclization of pinacolborane chalcone derivatives 105 using (R)-MonoPhos® as a chiral ligand [58]. In this reaction, a wide variety of 1-indanones 107 were obtained in high yields and up to 95

• -indanones 159a–g by a rhodium-catalyzed isomerization of racemic α-arylpropargyl alcohols 158 has been developed by Shintani, Okamoto and Hayashi (Scheme 46) [76]. By the mechanistic investigations using deuterium-labeled substrates, the authors have disclosed that the methine proton of the alcohol goes to

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• ]. Opatz et al. developed the enantioselective syntheses of various alkaloids using the rhodium catalyst developed by Noyori [88] for the asymmetric transfer hydrogenation of imines. Interestingly, imines are formed from unstable α-aminonitrile intermediates which spontaneously eliminate HCN [89][90][91

• coordinating substituent on the C atom linked to the cyano group disfavors the reductive decyanation. Rhodium-catalyzed reductive decyanation Chatani and co-workers have investigated the rhodium-catalyzed carbon–cyano bond cleavage reactions using organosilicon reagents [94]. They reported a rhodium-catalyzed

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

• Ming Liu,
• Jan C. Namyslo,
• Martin Nieger,
• Mika Polamo and
• Andreas Schmidt

Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264

• taken in the anion detection mode show the peak of 10 as base peak at m/z = 627. The anionic N-heterocyclic carbene 7 also forms a rhodium and a nickel complex (Scheme 2). The colorless rhodium complex [Rh(7)3] 11 was prepared on reaction of the tautomeric mixture 6A/B with either chlorido(1,5

• -cyclooctadiene)rhodium(I) dimer, or with bis(triphenylphosphine)rhodium(I) carbonyl chloride in anhydrous toluene at reflux temperature, respectively. During these reactions, the water of crystallization of the starting material is – at least partially – removed by azeotropic distillation and Rh(I) is obviously

• chemical shifts are in a more upfield region and the coupling constants are smaller than in other complexes such as the neutral N-heterocyclic oxocarbene (NHOC) rhodium complex ([Rh(NHOC)Cl(COD)] of 2 (R = Mes; δCcarbene = 229.7 ppm; 1JRhCcarbene = 51.5 Hz) as well as its enol ethers (δCcarbene = 171–177

Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis

• Darcy J. Atkinson,
• Briar J. Naysmith,
• Daniel P. Furkert and
• Margaret A. Brimble

Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226

• (1) and (±)-allo-enduracididine (3) reported by Du Bois et al. arose from the methodology for the conversion of alkenes to diamines via a cyclic sulfonamide intermediate using rhodium catalysis (Scheme 9) [63]. The reaction proceeds with formation of an intermediate aziridine 53 which rearranges upon

Organometallic chemistry

• Bernd F. Straub,
• Rolf Gleiter,
• Claudia Meier and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 2216–2221, doi:10.3762/bjoc.12.213

• improved understanding of this industrially important process was achieved by a combination of ligand design for the rhodium catalysts, kinetic studies, and high-level quantum-chemical calculations [126][135][142][145][146][152][155]. In 2006, he initiated the foundation of the “Catalysis Research

Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols

• Katrina Tait,
• Oday Alrifai,
• Rebecca Boutin,
• Jamie Haner and
• William Tam

Beilstein J. Org. Chem. 2016, 12, 2189–2196, doi:10.3762/bjoc.12.209

• ). Syn-stereoisomeric products 2 and 3 can be obtained using rhodium [14], palladium [15], or nickel [16] catalysts with an arene nucleophile and when palladium [17] or nickel [18] are used with an alkyl nucleophile. Recently, it was shown that the syn-stereoisomeric product 4 could be obtained through

• the use of platinum catalysts [19] or palladium catalysts with zinc co-catalyst with phenol nucleophiles [20]. Meanwhile, anti-stereoisomeric products 5 and 6 are obtained when copper catalysts are used with alkyl nucleophiles [21], if rhodium [22] or iridium catalysts are used in the presence of

Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N–H-insertion products

• Valerij A. Nikolaev,
• Jury J. Medvedev,
• Olesia S. Galkina,
• Ksenia V. Azarova and
• Christoph Schneider

Beilstein J. Org. Chem. 2016, 12, 1904–1910, doi:10.3762/bjoc.12.180

• catalyst and its ligands on the efficiency of the processes studied, non-fluorinated rhodium carboxylates (Rh2L4; L = OAc, Oct, Piv) and catalysts with trifluoroacetate or perfluorobutyrate ligands [Rh2L4; L = CF3CO2 (tfa), C3F7CO2 (pfb)] were used in this research. Results and Discussion In the beginning

• without the addition of TEMPO, though with lower yields [29]. Recently, communications appeared related to similar oxidation processes with participation of rhodium catalysts [30][31][32][33]. Based on the literature data [29][34][35] and our current research, one can propose a mechanism for the

• -known for decomposition reactions of diazocarbonyl compounds using Cu and Fe catalysts [29] and in some cases with the employment of Rh-carboxylates as well [30]. Ketoamine F proves to be unstable under the reaction conditions and is oxidized by a rhodium catalyst complex with oxygen producing

Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes

• Michael Nonnenmacher,
• Dominik M. Buck and
• Doris Kunz

Beilstein J. Org. Chem. 2016, 12, 1884–1896, doi:10.3762/bjoc.12.178

• ; electron donor character; N-heterocyclic carbene; rhodium; Introduction N-Heterocyclic carbenes form a ligand class that is typically characterized by a strong σ-donor and a weak or even negligible π-acceptor effect [1][2][3], although Meyer has shown pronounced π-acceptor ability in Cu complexes [4][5][6

• carbenes derived from imidazole so far. This overcompensates even the lower σ-donor character, so that their overall electron-donating ability lies in between that of acyclic diaminocarbenes and saturated NHCs. Results and Discussion Synthesis of the rhodium CO and 13CO complexes 2a and 2b We generated the

• of the CO ligand by phosphines in [M(CO)2Cl(NHC)] complexes (M = Rh, Ir) or even by DMSO [60][61][62] occurs at the trans-CO ligand. In some cases, loss of CO upon formation of dimers can be observed for rhodium NHC complexes [63][64][65]. Ligand exchange in square planar Rh(I) carbonyl complexes was

Rh-Catalyzed reductive Mannich-type reaction and its application towards the synthesis of (±)-ezetimibe

• Motoyuki Isoda,
• Kazuyuki Sato,
• Yurika Kunugi,
• Satsuki Tokonishi,
• Atsushi Tarui,
• Masaaki Omote,
• Hideki Minami and
• Akira Ando

Beilstein J. Org. Chem. 2016, 12, 1608–1615, doi:10.3762/bjoc.12.157

• -1 Hirokoshingai, Kure, Hiroshima 737-0112, Japan 10.3762/bjoc.12.157 Abstract An effective synthesis for syn-β-lactams was achieved using a Rh-catalyzed reductive Mannich-type reaction. A rhodium–hydride complex (Rh–H) derived from diethylzinc (Et2Zn) and a Rh catalyst was used for the 1,4

• Mannich-type reaction; rhodium–hydride; zinc enolate; Introduction The Mannich reaction is an important and classical C–C bond-forming reaction between an enolizable carbonyl compound and an imine to give the corresponding β-aminocarbonyl compound. For example, Shibasaki and his colleague reported the

• yield was 46%. In some of our previous publications [22][23][36], we proposed a reaction mechanism as shown in Figure 1. In the initial step, the Rh catalyst reacted with Et2Zn to give a rhodium–hydride complex 6 via the elimination of ethylene from the rhodium–ethyl complex 5. The formation of rhodium

Microwave-assisted synthesis of (aminomethylene)bisphosphine oxides and (aminomethylene)bisphosphonates by a three-component condensation

• Erika Bálint,
• Ádám Tajti,
• Anna Dzielak,
• Gerhard Hägele and
• György Keglevich

Beilstein J. Org. Chem. 2016, 12, 1493–1502, doi:10.3762/bjoc.12.146

• ]. (Aminomethylene)bisphosphonates can also be obtained starting from amides, triethyl phosphite and phosphorus oxychloride (Scheme 3a) [37], or in the reaction of amines with diazophosphonate in the presence of a rhodium catalyst (Scheme 3b) [38]. (Aminomethylene)bisphosphine oxides are analogous to (aminomethylene

Stereodynamic tetrahydrobiisoindole “NU-BIPHEP(O)”s: functionalization, rotational barriers and non-covalent interactions

• Golo Storch,
• Sebastian Pallmann,
• Frank Rominger and
• Oliver Trapp

Beilstein J. Org. Chem. 2016, 12, 1453–1458, doi:10.3762/bjoc.12.141

• -BIPHEPs” are a class of stereodynamic diphosphine ligands which are easily accessible via rhodium-catalyzed double [2 + 2 + 2] cycloadditions. This study explores the preparation of differently functionalized “NU-BIPHEP(O)” compounds, the characterization of non-covalent adduct formation and the

• Mikami reported the stereochemical alignment of BIPHEP ligands in ruthenium complexes upon addition of chiral diamine co-ligands [1][2]. The resulting complexes were successfully employed in enantioselective ketone hydrogenation. Further examples of such systems are BIPHEP complexes of rhodium [3][4][5

• phases [22]. However, introduction of functional groups which enable a modular derivatization approach is often hampered by long and tedious synthetic procedures. Doherty et al. reported a rhodium catalyzed double [2 + 2 + 2] cycloaddition strategy for a convergent synthesis of “NU-BIPHEP”s [23]. In this

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• has been the use of rhodium(I) transition metal catalysts and axially chiral phosphorous ligands (Figure 2). Additionally, because organometallic reagents are often utilized as nucleophiles, an exogenous proton source, which can impact the transformation’s enantioselectivity, is frequently needed. In

• this context, Reetz and co-workers were the first to report the transition metal-catalyzed enantioselective addition of arylboronic acids to an α-substituted-α,β-unsaturated ester to provide enantioenriched phenylalanine derivatives 48a (Scheme 10) [29]. Notably, a BINAP-derived rhodium(I) catalyst was

• itaconate (50) in the presence of a rhodium(I) catalyst and (R)-BINAP ligand (43, Figure 2) [31]. During optimization they found that switching to potassium organotrifluoroborates from organoboronic acids was necessary to achieve high enantioinduction. Additionally, the enantioselectivity was highly

NeoPHOX – a structurally tunable ligand system for asymmetric catalysis

• Jaroslav Padevět,
• Marcus G. Schrems,
• Robin Scheil and
• Andreas Pfaltz

Beilstein J. Org. Chem. 2016, 12, 1185–1195, doi:10.3762/bjoc.12.114

• as a widely used privileged ligand class [4][5][6][7][8][9][10][11][12]. One of the major areas of application of PHOX and related N,P ligands is the iridium-catalyzed asymmetric hydrogenation [13][14][15][16]. Compared to rhodium and ruthenium catalysts, iridium complexes derived from chiral N,P

Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

• Barry M. Trost,
• Michael C. Ryan and
• Meera Rao

Beilstein J. Org. Chem. 2016, 12, 1136–1152, doi:10.3762/bjoc.12.110

• and selectivity [24] (Scheme 2a). Unfortunately, the scope of this reaction is rather limited, as this is the only example presented in the paper. Mechanistic studies performed by the same group on this system support a hydropalladation/cyclization/β-hydride elimination mechanism. Rhodium catalysis of

• functionality on the substrate in question. For example, Hayashi has shown that a rhodium/phosphoramidite catalysis is particularly effective for asymmetric [5 + 2] cycloaddition reactions (Scheme 2b). The (S,R,R)-diastereomer of the Feringa-style phosphoramidite ligand proved to be crucial to both the yield

• rhodium first undergoes oxidative cyclization with the vinylcyclopropane prior to alkyne insertion. The asymmetric enyne cycloisomerization reaction has been shown to be instrumental in the construction of medicinal chemistry targets. For example, the Fürstner group realized that gold catalysis would be

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• the rotation about the ketone–cyclohexyl bond so that the carbene may be conformationally disposed over the ring as shown in 31 instead of the exocyclic conformation 33. Rhodium The most common metal seen in C–H bond insertions for the formation of bridged rings is rhodium. Adams used Rh2(OAc)4 to

• conformation of the cyclooctyl ring may also play a role in the selectivity as discussed below. The White group used rhodium dimers as catalysts to form the central quaternary carbon of (+)-codeine (Scheme 9) [62]. This insertion into the benzylic methine of 43 was quite selective, with only a single reported

• –H bond insertion using Wilkinson’s catalyst (RhCl(PPh3)3) instead of the usual rhodium(II) dimer (Scheme 13) [68]. Rather than starting with a diazoketone, ester, or amide, Wilkinson’s catalyst may generate an active organorhodium intermediate through insertion into the acyl C–H bond of the aldehyde

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• promote the formation of a specific enantiomer. The search for the best balance of these properties of the carbenoid intermediates was also sought through the use of different metals such as copper [3], rhodium [4], iron [5], ruthenium [6], iridium [7], osmium [8], and others. From these, copper and

• rhodium have been the most frequently used ones in carbenoid insertion reactions. Copper carbenoids having a higher electrophilic character display a great reactivity, but little selectivity in insertion reactions. Despite these features, only recently the insertion of chiral copper carbenoids into a C

• (sp3)–H bond has gained special attention, as in the works of Muler and Boléa [9], Flynn [10], Stattery [11] and their respective co-workers. The most selective copper carbenoids are those generated from chiral bis(oxazoline) ligands in the presence of copper(I) triflate (CuOTf) (Figure 3). The rhodium

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

• neutral κ2-P,N-ligands comprising an imine and a phosphine binding site. These ligands were reacted with rhodium, iridium and palladium metal precursors and the structures of the resulting complexes were elucidated by means of X-ray crystallography. We observed that subtle changes of the ligand backbone

• donors, with distinct consequences for their coordination chemistry (vide infra). Complex synthesis In the next step of our study we set out to explore the coordination chemistry and structural properties of the synthesized ligands with rhodium(I/III), iridium(I/III) and palladium(II) precursors

• . Reaction of ligands 2 and 3 with (i) preformed [Rh(cod)2]BF4 and (ii) stoichiometric amounts of [Ir(cod)Cl]2 in the presence of AgBF4 gave the corresponding rhodium(I) and iridium(I) complexes [2,3-M(cod)]BF4 in good to excellent yields (Scheme 3). In a similar fashion, analogous complexes of ligands 5 and