Surprisingly facile CO₂ insertion into cobalt alkoxide bonds: A theoretical investigation

• Willem K. Offermans,
• Claudia Bizzarri,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 1340–1351, doi:10.3762/bjoc.11.144

• cycloaddition. Direct catalytic carboxylation of aliphatic compounds and arenes by rhodium(I)– and ruthenium(II)–pincer complexes, respectively. Insertion of carbon dioxide into a metal–oxygen bond via a cyclic four-membered transition state. R is either an aliphatic or aromatic group. Facile CO2 uptake by zinc

Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Ongolu Ravikumar

Beilstein J. Org. Chem. 2015, 11, 1259–1264, doi:10.3762/bjoc.11.140

• used to design new polycycles. In this regard, ruthenium alkylidene catalysts are effective in realizing the RRM of bis-norbornene derivatives prepared by DA reaction and Grignard addition. Here, fused polycycles are assembled which are difficult to produce by conventional synthetic routes. Keywords

• ; HRMS (Q–ToF) m/z: [M + Na]+ calcd for C25H32NaO2, 387.2295; found, 387.2292. Commercially available ruthenium catalysts used in RRM metathesis. Crystal structure of 5 with thermal ellipsoids drawn at 50% probability level. Synthesis of hexacyclic compound 6a by using an RRM approach. Synthesis of

Interactions between tetrathiafulvalene units in dimeric structures – the influence of cyclic cores

• Huixin Jiang,
• Virginia Mazzanti,
• Christian R. Parker,
• Søren Lindbæk Broman,
• Jens Heide Wallberg,
• Karol Lušpai,
• Adam Brincko,
• Henrik G. Kjaergaard,
• Anders Kadziola,
• Peter Rapta,
• Ole Hammerich and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2015, 11, 930–948, doi:10.3762/bjoc.11.104

• [11][12] have shown how rotamers can indeed influence the electronic coupling in bis-ruthenium complexes separated by oligoynediyl spacers. In addition, an increased interaction between redox centres upon linking them together in cyclic structures was previously observed in ferrocene-dimers [13]. Here

Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

• Alireza Shakoori,
• John B. Bremner,
• Mohammed K. Abdel-Hamid,
• Anthony C. Willis,
• Rachada Haritakun and
• Paul A. Keller

Beilstein J. Org. Chem. 2015, 11, 481–492, doi:10.3762/bjoc.11.54

• ' reagent. This is not unexpected as there are reports of ruthenium-based species catalysing Claisen rearrangements [7] including a similar RCM–Claisen sequence in 2,2'-bis(allyloxy)-1,1'-binaphthyls and O,O'-(but-2-en-1,4-diyl) binaphthols [12][13]. Additionally, examples of C2 to C3 Claisen rearrangement

Ruthenium-catalyzed C–H activation of thioxanthones

• Danny Wagner and
• Stefan Bräse

Beilstein J. Org. Chem. 2015, 11, 431–436, doi:10.3762/bjoc.11.49

• /bjoc.11.49 Abstract Thioxanthones – being readily available in one step from thiosalicylic acid and arenes – were used in ruthenium-catalyzed C–H-activation reaction to produce 1-mono- or 1,8-disubstituted thioxanthones in good to excellent yields. Scope and limitation of this reaction are presented

Eosin Y-catalyzed visible-light-mediated aerobic oxidative cyclization of N,N-dimethylanilines with maleimides

• Zhongwei Liang,
• Song Xu,
• Wenyan Tian and
• Ronghua Zhang

Beilstein J. Org. Chem. 2015, 11, 425–430, doi:10.3762/bjoc.11.48

• light, which is clean, abundant, and renewable. The pioneering work in this research area, reported by the groups of MacMillan [7][8][9], Yoon [10][11], Stephenson [12][13] and others [14][15][16][17][18], has demonstrated that ruthenium and iridium complexes as visible light photoredox catalysts are

• capable of catalyzing a broad range of useful reactions. A variety of new methods have been developed to accomplish known and new chemical transformations by means of these transition metal-based photocatalysts so far. However, the ruthenium and iridium catalysts usually are high-cost, potentially toxic

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

• -containing moieties (amide, pyridine, oxime, etc.) are most commonly used as directing groups, which are responsible for the regioselectivity of the C–O coupling. Most transformations of this type are catalyzed by Pd(II) compounds. Examples of the use of copper and ruthenium compounds as catalysts were also

• [55], and O-acetyl aryl oximes [56] in the presence of the Pd(OAc)2/PhI(OAc)2 system were described. The ruthenium-catalyzed ortho-acyloxylation of acetanilides 39 with carboxylic acids in the presence of AgSbF6 and ammonium persulfate afforded products 40 (Scheme 8) [57]. This method can be used for

• 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

Morita–Baylis–Hillman reaction of acrylamide with isatin derivatives

• Radhey M. Singh,
• Kishor Chandra Bharadwaj and
• Dharmendra Kumar Tiwari

Beilstein J. Org. Chem. 2014, 10, 2975–2980, doi:10.3762/bjoc.10.315

• appending other functionalities/groups for intramolecular transformations. Other reports have used this feature for the development of an intramolecular MBH reaction: Corey et al. (total synthesis) [29], Pigge et al. (ruthenium complexes as an electrophile) [30], and Basavaiah et al. [31][32]. Isatin has

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• ethidium bromide–ruthenium(II) complex also proved to be an imaging probe whose fluorescence intensity and lifetime changes substantially in the presence of RNA [85], thus supporting a strategy of phenanthridinium incorporation into the heterogenic two-chromophore system. Phenanthridines are rarely

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation

• Yiyang Liu,
• Marc Liniger,
• Ryan M. McFadden,
• Jenny L. Roizen,
• Jacquie Malette,
• Corey M. Reeves,
• Douglas C. Behenna,
• Masaki Seto,
• Jimin Kim,
• Justin T. Mohr,
• Scott C. Virgil and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2014, 10, 2501–2512, doi:10.3762/bjoc.10.261

• using a chiral auxiliary strategy. We envisioned that chiral lactam 60 could again be readily accessed by our palladium-catalyzed enantioselective alkylation chemistry. The formal synthesis of (−)-vincadifformine commenced with ruthenium-catalyzed isomerization of the terminal olefin moiety in

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

• . Ow stands for water molecules. Ruthenium complexes 7 and 8 in Newman projection along the Ru–P bond. Titration of HUGPHOS-1 with [Rh(CO)2Cl]2 at 25 °C. High pressure NMR spectra of 13 under CO/H2 (1:1) recorded in toluene-d8 (at various temperatures and pressures), showing its conversion into trans

Amino acid motifs in natural products: synthesis of O-acylated derivatives of (2S,3S)-3-hydroxyleucine

• Oliver Ries,
• Martin Büschleb,
• Markus Granitzka,
• Dietmar Stalke and
• Christian Ducho

Beilstein J. Org. Chem. 2014, 10, 1135–1142, doi:10.3762/bjoc.10.113

• primary alcohol 9 (obtained in 80% yield) was oxidized to carboxylic acid 11 by ruthenium(III)-catalyzed periodate oxidation in 82% yield. Subsequent protection of the acid functionality furnished 2-(trimethylsilyl)ethyl (TMSE) and benzyl esters 12a and 12b (yields 72% and 84%, respectively). Finally

Direct C–H trifluoromethylation of di- and trisubstituted alkenes by photoredox catalysis

• Ren Tomita,
• Yusuke Yasu,
• Takashi Koike and
• Munetaka Akita

Beilstein J. Org. Chem. 2014, 10, 1099–1106, doi:10.3762/bjoc.10.108

• a CF3 group into diverse skeletons has become a hot research topic in the field of organic synthetic chemistry [7][8][9][10][11][12]. Recently, radical trifluoromethylation by photoredox catalysis [13][14][15][16][17][18][19][20][21][22][23] with ruthenium(II) polypyridine complexes (e.g., [Ru(bpy)3

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

• -coupling of benzyl or alkyl halides with racemic secondary phosphines have been developed. These reactions were catalyzed by chiral platinum or ruthenium complexes. The enantioselectivity is based on a dynamic kinetic resolution. Upon reaction with the catalyst precursor containing a chiral ligand (L*), a

• reactions of secondary phosphines with several electrophiles, including alkyl halides (alkylation), alkenes (hydrophosphination) and aryl iodides (arylation). Chan et al. synthesized P-stereogenic phosphine boranes using a ruthenium catalyst. The secondary phosphine 36a underwent an enantioselective

• alkylation to 12c (Scheme 11). The mechanism of the reaction is based on the formation of an electron-rich ruthenium–phosphido complex that enhances the nucleophilicity at the phosphorus atom. This permitted the reaction to proceed with the less electrophilic benzylic chlorides 35 instead of bromides. The

Olefin cross metathesis based de novo synthesis of a partially protected L-amicetose and a fully protected L-cinerulose derivative

• Bernd Schmidt and
• Sylvia Hauke

Beilstein J. Org. Chem. 2014, 10, 1023–1031, doi:10.3762/bjoc.10.102

• -benzoate protected L-amicetose and a cinerulose derivative protected at C5 and C1. Keywords: carbohydrates; de novo synthesis; lactate; metathesis; ruthenium; Introduction Many drugs and bioactive natural products are glycoconjugates, which contain an aglycon part linked through glycosidic bonds to one

Visible-light-induced, Ir-catalyzed reactions of N-methyl-N-((trimethylsilyl)methyl)aniline with cyclic α,β-unsaturated carbonyl compounds

• Dominik Lenhart and
• Thorsten Bach

Beilstein J. Org. Chem. 2014, 10, 890–896, doi:10.3762/bjoc.10.86

• not observed. Contrary to that, the ruthenium catalyst Ru(bpy)3Cl2 delivered a mixture of both products in a ratio of 77/23. Apart from CH2Cl2, other solvents were tested (see Supporting Information File 2), none of which led to a significant yield improvement. It was observed, however, that the

Metal and metal-free photocatalysts: mechanistic approach and application as photoinitiators of photopolymerization

• Jacques Lalevée,
• Sofia Telitel,
• Pu Xiao,
• Marc Lepeltier,
• Frédéric Dumur,
• Fabrice Morlet-Savary,
• Didier Gigmes and
• Jean-Pierre Fouassier

Beilstein J. Org. Chem. 2014, 10, 863–876, doi:10.3762/bjoc.10.83

• of sustainable radical-mediated chemical processes under very soft irradiation conditions (e.g., household fluorescence or LED bulbs, halogen lamps, sunlight, Xe lamp), e.g., enantioselective alkylation, cycloaddition, etc. [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Ruthenium- and iridium-based

• ], the introduction of the silane also reduces the oxygen inhibition of the radical stages of the FRP and FRPCP reactions. Many photoinitiating systems have been designed on the basis of Scheme 6 [45][46][47][48][49][50][51][52]. Ruthenium and iridium-containing PICs are relatively well known and a large

The Flögel-three-component reaction with dicarboxylic acids – an approach to bis(β-alkoxy-β-ketoenamides) for the synthesis of complex pyridine and pyrimidine derivatives

• Mrinal K. Bera,
• Moisés Domínguez,
• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 394–404, doi:10.3762/bjoc.10.37

• catalysis. With ruthenium-based catalysts bearing N-heterocyclic carbene (NHC) ligands, RCM usually delivers macrocyclic olefins as mixtures of E- and Z-isomers, in most cases in favor of the E-isomer [70][71][72][73]. The E/Z-ratio is often under thermodynamic control, reflecting the energy difference

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• methodology [62][63][64]. The combination of the catalytic hetero-Diels–Alder/allyboration sequence with a ruthenium-catalyzed isomerization gave access to the 6,8-dioxabicyclo[3.2.1]octane skeleton of (+)-iso-exo-brevicomin (26, Scheme 18) [65]. When a Z/E mixture of 2-substituted enol ethers was used as

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• 96, for which the yield and enantioselectivity was determined starting from 93. Standard functional group interconversion first provided exo-methylene 97, followed by ruthenium-catalyzed oxidative cleavage of the installed exo-methylene moiety [94] to give tricyclic ketone 98, which can be converted

• towards the total synthesis of salvileucalin B (292, see Scheme 35) isolated from the plant Salvia leucantha [213]. Starting from enantiopure trialkyne 282, desilylation was affected using TBAF, followed by ruthenium-catalyzed cycloisomerization [214] and cleavage of the chiral auxiliary to obtain

• organoiron route towards the guianolide skeleton. Stoltz’s tandem Wolff/DVCPR rearrangement. Stephenson’s tandem photocatalysis/arylvinylcyclopropane rearrangement. Padwa’s rhodium cascade involving a DVCPR. Matsubara’s version of a DVCPR. Toste’s tandem gold-catalyzed Claisen-rearrangement/DVCPR. Ruthenium

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• % yields. 2,4,6-Triphenylpyrylium tetrafluoroborate was used as the sensitizer for singlet oxygen generation (Scheme 54) [301]. It was found that tris(bipyrazyl)ruthenium(II) [(Ru(bpz)3(PF6)2] is an excellent photocatalyst for the synthesis of 1,2-dioxanes by aerobic photooxygenation of α,ω-dienes [302

The difluoromethylene (CF₂) group in aliphatic chains: Synthesis and conformational preference of palmitic acids and nonadecane containing CF₂ groups

• Yi Wang,
• Ricardo Callejo,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2014, 10, 18–25, doi:10.3762/bjoc.10.4

• ketones, to generate difluoromethyleneacetylenes, is methodology developed by Grée et al. [14][15][16][17][18] and it proved to be very reliable in our hands. An efficient hydrogenation generated the C-8 substituted difluoromethylenepentadecabenzene 12. Finally biphasic ruthenium tetroxide-catalyzed aryl

A unified approach to the important protein kinase inhibitor balanol and a proposed analogue

• Tapan Saha,
• Ratnava Maitra and
• Shital K. Chattopadhyay

Beilstein J. Org. Chem. 2013, 9, 2910–2915, doi:10.3762/bjoc.9.327

• generation catalyst, benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro-(tricyclohexylphosphine)ruthenium (25). Pleasingly, the desired cycloalkene 26 was obtained in a gratifying yield of 89%. The sequential removal of the O-acetyl group leading to 27 followed by removal of the N-Boc

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• published literature utilising 4-iodoanisole and methyl acrylate in the presence of ruthenium- and platinum-complex catalysts, in which complete regioselectivity towards the trans-isomer was achieved [19]. Having obtained encouraging conversions in the 1 mm diameter reactor, it was decided to scale the

Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C₂-symmetric building block: a strategy for the synthesis of decanolide natural products

• Bernd Schmidt and
• Oliver Kunz

Beilstein J. Org. Chem. 2013, 9, 2544–2555, doi:10.3762/bjoc.9.289

• ; natural products; ruthenium; Introduction Bidirectional synthesis through termini differentiation of meso, C2-symmetric or unsymmetric building blocks has emerged as an important strategy in natural product synthesis over the past two decades [1]. Early on, enantiomerically pure C2-symmetric compounds