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

• and co-workers described metal-catalysed tandem Diels–Alder/hydrolysis reactions of 2-boron-substituted 1,3-dienes [54][55]. Boron-dienes containing various ligands reacted with maleimides in the presence of rhodium and copper catalysts using BINAP as ligand (Scheme 15). NMR analysis of the crude

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

• 82. Diazotransfer using p-ABSA [86] yielded diazoester 83. Selective rhodium-catalyzed cyclopropanation of the cis-double bond [87][88] of diene 84 [89] furnished cis-divinylcyclopropane 85, which underwent DVCPR upon Kugelrohr distillation at 140 °C to give bicyclic 86. Selective hydrogenation of

• detected in the human body after cocaine consumption. It can be degradatively accessed from cocaine through pyrolysis, cocaine congeners can be prepared via conjugate addition afterwards [113][114]. Boc-protected pyrrole 127 was subjected to rhodium-catalyzed cyclopropanation with vinyldiazo compound 128

• . Removal of the MOM-protecting group followed by reduction of the amide concluded Fukuyama’s total synthesis of gelsemine (146). An approach similar to Davies formal [4 + 3]-cycloaddition [81] was used by the group of Kende [130] to access the alkaloid isostemofoline (158, see Scheme 19) [131]. Rhodium

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

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• ) is hydrogenated to the vinylogous carbamate 2.53 in the presence of acetic anhydride. Then the intermediate 2.53 can be subjected to an asymmetric hydrogenation utilising rhodium-based catalyst systems at elevated hydrogen pressures rendering the desired ethyl (R)-nipecotate 2.54 [75]. Uniting the

Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors

• Rahat Javaid,
• Shin-ichiro Kawasaki,
• Akira Suzuki and
• Toshishige M. Suzuki

Beilstein J. Org. Chem. 2013, 9, 1156–1163, doi:10.3762/bjoc.9.129

• thin (1–2 μm) palladium (Pd), platinum (Pt), and rhodium (Rh) layers by an electroless plating procedure [10][11]. These tubular reactors combined the merit of flow reaction processing with the catalytic properties of various metals. Unlike packed-bed catalysts, hollow tubular reactors can minimize the

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

• ][51][52][53] or enolates [54] from simple alkynes by carbocupration reactions. Not only copper but also rhodium can catalyze carbometalation reactions. Hayashi applied carborhodation chemistry [55][56][57][58] to the reactions of aryl alkynyl ketones with arylzinc reagents, which provided enolates of

• indanones (Scheme 4) [59]. Phenylrhodation of 1g first proceeds to form 1A. A subsequent intramolecular 1,4-hydrogen shift gives 1B, which smoothly undergoes an intramolecular 1,4-addition to yield 1C. Finally, transmetalation from the phenylzinc reagent to rhodium enolate 1C affords zinc enolate 1h, which

• directing group to control the regioselectivity to afford 2E (Scheme 13, path B) [25][74][75][76]. In 2009, Lam reported the rhodium-catalyzed carbozincation of ynamides. The reaction smoothly proceeded under mild conditions to provide the corresponding intermediate 2i regioselectively (Scheme 14) [77][78

Alkyne hydroarylation with Au N-heterocyclic carbene catalysts

• Cristina Tubaro,
• Marco Baron,
• Andrea Biffis and
• Marino Basato

Beilstein J. Org. Chem. 2013, 9, 246–253, doi:10.3762/bjoc.9.29

• ], gold [18][19], or rhodium [20], as well as of non-noble, electrophilic metals [21][22][23][24][25][26] have also been successfully employed. Finally, an even greater number of catalysts have been proposed over the years to promote alkyne hydroarylation in an intramolecular fashion [1][2][3][4][5][6][7

Iron-containing mesoporous aluminosilicate catalyzed direct alkenylation of phenols: Facile synthesis of 1,1-diarylalkenes

• Satyajit Haldar and
• Subratanath Koner

Beilstein J. Org. Chem. 2013, 9, 49–55, doi:10.3762/bjoc.9.6

• ][23]. In general, the reaction shows β-selectivity, and there are only a few reports available concerned with α-substituted products [24][25][26]. Sabarre and Love reported a one-pot rhodium-catalyzed alkyne hydrothiolation followed by a nickel-catalyzed Kumada-type cross coupling with Grignard

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• , thus, gave data ideally suited to mechanistic studies [56]. The potential of microreactors in the photocatalytic splitting of water has also come under investigation. In this case a rhodium-containing inorganic photocatalyst was employed, and again online QMS permitted mechanistic studies to be

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

Rh(III)-catalyzed directed C–H bond amidation of ferrocenes with isocyanates

• Satoshi Takebayashi,
• Tsubasa Shizuno,
• Takashi Otani and
• Takanori Shibata

Beilstein J. Org. Chem. 2012, 8, 1844–1848, doi:10.3762/bjoc.8.212

• ; ferrocene; rhodium; Introduction Ferrocene and its derivatives are among the most useful organometallic compounds because of their chemical and thermal stabilities, structures, and redox activity [1][2]. One of the most remarkable applications of ferrocene derivatives is as chiral ligands [3][4]. A variety

Evaluation of a chiral cubane-based Schiff base ligand in asymmetric catalysis reactions

• Kyle F. Biegasiewicz,
• Michelle L. Ingalsbe,
• Jeffrey D. St. Denis,
• James L. Gleason,
• Junming Ho,
• Michelle L. Coote,
• G. Paul Savage and
• Ronny Priefer

Beilstein J. Org. Chem. 2012, 8, 1814–1818, doi:10.3762/bjoc.8.207

• (MAO) inactivators [8][9][10]. Cubanes have also shown a propensity to undergo cage opening. In particular, syn-tricyclooctadienes are formed when rhodium(I) salts are introduced [11], while with silver(I) or palladium(II) catalysts, cuneane is obtained [12]. Spontaneous cage opening has been observed

Copper-catalyzed CuAAC/intramolecular C–H arylation sequence: Synthesis of annulated 1,2,3-triazoles

• Rajkumar Jeyachandran,
• Harish Kumar Potukuchi and
• Lutz Ackermann

Beilstein J. Org. Chem. 2012, 8, 1771–1777, doi:10.3762/bjoc.8.202

• ][16]. This streamlining of organic synthesis has predominantly been accomplished with palladium [4][5][6][7][8][9][10][11][12][13][14][15][16], rhodium [17][18][19] or ruthenium [20][21][22] complexes [4][5][6][7][8][9][10][11][12][13][14][15][16]. However, less expensive nickel, cobalt, iron or

C2-Alkylation of N-pyrimidylindole with vinylsilane via cobalt-catalyzed C–H bond activation

• Zhenhua Ding and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2012, 8, 1536–1542, doi:10.3762/bjoc.8.174

• as a directing group for rhodium-catalyzed C2-alkenylation [36], was entirely ineffective. Vinylsilanes bearing dimethylphenylsilyl and triphenylsilyl groups were amenable to the addition reaction with 1a, affording the adduct 3ab and 3ac in modest yields. Vinyltriethoxysilane also reacted with 1a in

N-Heterocyclic carbene-catalyzed direct cross-aza-benzoin reaction: Efficient synthesis of α-amino-β-keto esters

• Takuya Uno,
• Yusuke Kobayashi and
• Yoshiji Takemoto

Beilstein J. Org. Chem. 2012, 8, 1499–1504, doi:10.3762/bjoc.8.169

• migration of the N-acyl glycine derivatives [18]. The other consists of C–N bond-forming reactions, such as (c) a rhodium-catalyzed N–H insertion reaction with α-diazo-β-keto esters [19][20][21], and (d) α-oxidation of β-keto esters to the corresponding oximes and the subsequent hydrogenation [22]. However

Impact of cyclodextrins on the behavior of amphiphilic ligands in aqueous organometallic catalysis

• Hervé Bricout,
• Estelle Léonard,
• Christophe Len,
• David Landy,
• Frédéric Hapiot and
• Eric Monflier

Beilstein J. Org. Chem. 2012, 8, 1479–1484, doi:10.3762/bjoc.8.167

• substrates constitutes a real challenge not completely solved so far. Recently, we showed that an association of cyclodextrins (CDs) and amphiphilic phosphanes could significantly improve the catalytic performances in an aqueous rhodium-catalyzed hydroformylation of higher olefins [6]. Herein we clearly

Parallel and four-step synthesis of natural-product-inspired scaffolds through modular assembly and divergent cyclization

• Hiroki Oguri,
• Haruki Mizoguchi,
• Hideaki Oikawa,
• Aki Ishiyama,
• Masato Iwatsuki,
• Kazuhiko Otoguro and
• Satoshi Ōmura

Beilstein J. Org. Chem. 2012, 8, 930–940, doi:10.3762/bjoc.8.105

• diazotransfer, leading to cyclization precursors. The rhodium-catalyzed tandem cyclization and divergent cycloaddition gave rise to tetracyclic and hexacyclic scaffolds by the appropriate choice of dipolarophiles installed at modules 3 and 4. A different piperidine-based manifold 15 bearing an amino group was

• undertaken. Keywords: chemical diversity; divergent cyclization; indole alkaloids; modular assembly; rhodium-catalyzed cyclization–cycloaddition; skeletal and stereochemical diversity; Introduction Biologically intriguing natural products often possess cyclic scaffolds bearing dense arrays of functional

• 3. Rhodium(II)-catalyzed tandem cyclization–cycloaddition [19][20][21] of the tetraketide-like precursors produced distinct multicyclic scaffolds, 4 and 5, differing in the relative orientations of the substructures. This approach illustrates a systematic way of diversifying skeletal arrays in a

Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine

• Marc Enßle,
• Stefan Buck,
• Roland Werz and
• Gerhard Maas

Beilstein J. Org. Chem. 2012, 8, 433–440, doi:10.3762/bjoc.8.49

• three steps. Upon rhodium-catalysed dediazoniation, two intramolecular carbenoid reactions competed, namely the formation of a cyclic sulfonium ylide and that of a six-ring carbonyl ylide. The S-methyl and S-benzyl ylides 12a and b could be isolated, while S-allyl ylide 12c underwent a [2,3]-sigmatropic

• undergo inter- and intramolecular formation of N-, O-, S- and other ylides [1][2]. The benefit of these transformations, which are usually performed with rhodium- or copper-based catalysts, is given by subsequent rearrangement or addition reactions of the reactive ylides; several recent reviews [3][4][5

• racemisation. A sample of 8a, which was prepared from a slightly racemised sample of 6a (HPLC: 90:10 enantiomeric ratio of the derived methyl ester, which was prepared from 6a and dry methanol in the presence of excess chlorotrimethylsilane) on the latter route, had an enantiomeric ratio of 83:17. Rhodium

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• . The oxacalix[3]arene also formed a complex with rhodium. Elemental analysis supported a composition incorporating the H–Rh–C=O fragment. 1H NMR indicated that this was threaded through the macrocyclic annulus, based on the presence of a peak at −9.70 ppm, and infrared analysis showed a carbonyl

Synthesis of fused tricyclic amines unsubstituted at the ring-junction positions by a cascade condensation, cyclization, cycloaddition then decarbonylation strategy

• Iain Coldham,
• Adam J. M. Burrell,
• Hélène D. S. Guerrand,
• Luke Watson,
• Nathaniel G. Martin and
• Niall Oram

Beilstein J. Org. Chem. 2012, 8, 107–111, doi:10.3762/bjoc.8.11

• substituent must be sufficient to allow a successful decarbonylation (in comparison with substrate 16), possibly due to the reduced ability of the amine nitrogen atom to coordinate to the rhodium complex. Conclusion The chemistry described here provides a method to prepare fused tricyclic products in which

Synthesis of highly functionalized β-aminocyclopentanecarboxylate stereoisomers by reductive ring opening reaction of isoxazolines

• Melinda Nonn,
• Loránd Kiss,
• Reijo Sillanpää and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2012, 8, 100–106, doi:10.3762/bjoc.8.10

•  3). Combinations of NaBH4 (as a mild and selective reducing agent) with cobalt, nickel, iridium or rhodium halide have previously been employed for cleavage of the isoxazoline ring system, which is otherwise inert to NaBH4 without such metal halide additives [50]. Accordingly, we investigated the

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

• Cécile Verrier,
• Pierrik Lassalas,
• Laure Théveau,
• Guy Quéguiner,
• François Trécourt,
• Francis Marsais and
• Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

• with arylboronic acids providing the arylazolylpalladium complex, which delivers the product (Scheme 27b and Scheme 28b). Rhodium- and nickel-catalyzed direct arylation of oxazoles with halides The methodology for the Rh(I)-catalyzed direct substitutive coupling of azoles with halides was developed by

• )-catalyzed direct arylation of benzoxazole with arylboronic acids [76]; (a) procedure; (b) proposed mechanism. Ni(II)-catalyzed direct arylation of benzoxazoles with arylboronic acids under O2 [76]; (a) procedure; (b) proposed mechanism. Rhodium-catalyzed direct arylation of benzoxazole [78][79]. Ni(II

Recent developments in gold-catalyzed cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2011, 7, 1075–1094, doi:10.3762/bjoc.7.124

• . Although transition metal-catalyzed cycloadditions have been known since the mid-20th century, it was not until the 80s and 90s that they were recognized as versatile and powerful synthetic tools. So far, most examples of transition metal-catalyzed cycloadditions have involved the use of rhodium, ruthenium

• cycloadditions involving zwitterionic intermediates similar to I have also been developed with other transition metal catalysts such as tungsten, rhodium or platinum [32][33][34][35]. In particular, important developments were recently achieved with platinum catalysts [36][37], including the first

• transformation is somewhat related to those previously described by Doyle and by Barluenga that involved α,β-unsaturated imines and rhodium–vinyl carbenoids (Doyle) or Fischer carbenes (Barluenga). However, the stereochemical outcome of these three processes is different [78][79]. Therefore, the reactivity of

Asymmetric Au-catalyzed cycloisomerization of 1,6-enynes: An entry to bicyclo[4.1.0]heptene

• Alexandre Pradal,
• Chung-Meng Chao,
• Patrick Y. Toullec and
• Véronique Michelet

Beilstein J. Org. Chem. 2011, 7, 1021–1029, doi:10.3762/bjoc.7.116

• chiral iridium catalyst [41] (Scheme 1, reaction 2). We and others recently pursued the improvement and development of this enantioselective process, by employing platinum [42][43][44], rhodium [45] or gold [46][47][48] complexes. Following our previous work with chiral gold catalysts [46], we report a

• % isolated yield respectively) resulting from 5-exo- and 6-endo cycloisomerization reactions [20][66]. Thus, the gold catalytic system cannot compete with the results obtained for the cyclizations of nitrogen-tethered enynes in the presence of iridium, platinum or rhodium catalysts [41][42][43][44][45]. The

Cationic gold(I) axially chiral biaryl bisphosphine complex-catalyzed atropselective synthesis of heterobiaryls

• Tetsuro Shibuya,
• Kyosuke Nakamura and
• Ken Tanaka

Beilstein J. Org. Chem. 2011, 7, 944–950, doi:10.3762/bjoc.7.105

• -aryl-2-pyridones has already been achieved by rhodium catalyzed [2 + 2 + 2] cycloaddition [18], while the atropselective synthesis of 4-aryl-2-pyridones has not yet been realized. The application of this intramolecular hydroalkenylation reaction to the atropselective synthesis of 4-aryl-2-pyridones