Methyl isocyanide as a convertible functional group for the synthesis of spirocyclic oxindole γ-lactams via post-Ugi-4CR/transamidation/cyclization in a one-pot, three-step sequence

• Amarendar Reddy Maddirala and
• Peter R. Andreana

Beilstein J. Org. Chem. 2018, 14, 875–883, doi:10.3762/bjoc.14.74

• '-pyrrolidine]-2,5'-diones. Zhu et al. [38] reported 3-substituted-2-indolinones via a microwave-assisted post-Ugi-4CR/Buchwald–Hartwig reaction and another similar approach was illustrated by Van der Eycken et al. [39] for spiro[indoline-3,2'-pyrrole]-2,5'(1'H)-diones. In previous efforts to study 3

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• coupled with various phenols 152 at the more reactive 7-position under mild reaction conditions in presence of K2CO3 in acetic acid/DMF to give pyrazolo[1,5-a]pyrimidine derivative 153. Various aromatic amines 154 were then coupled at 5-postion under Buchwald–Hartwig conditions to get the desired 5

Synthesis of substituted Z-styrenes by Hiyama-type coupling of oxasilacycloalkenes: application to the synthesis of a 1-benzoxocane

• James R. Vyvyan,
• Courtney A. Engles,
• Scott L. Bray,
• Erik D. Wold,
• Christopher L. Porter and
• Mikhail O. Konev

Beilstein J. Org. Chem. 2017, 13, 2122–2127, doi:10.3762/bjoc.13.209

• -hydrosilylation of alkynols. One of the cross-coupling products was converted to a 1-benzoxocane, albeit in low yield, using an intramolecular Buchwald–Hartwig etherification. The cyclic ether produced contains the carbon skeleton of heliannuol A. Keywords: cross-coupling; heterocycles; hydrosilylation

• intramolecular Buchwald–Hartwig etherification of a Z-styrene derivative to provide a conformational constraint to facilitate the formation of the eight-membered ring [37]. The presence of the alkene reduces the conformational degrees of freedom in 2, thereby partially offsetting the entropic penalty of forming

• on the intramolecular Buchwald–Hartwig etherification [38][39][40] of bromoalcohol 15 to prepare eight-membered cyclic ether 24 (Table 2). The use of Pd(II) catalyst precursors with BINAP ligands and carbonate bases in toluene [38][39] was ineffective, returning significant amounts of unreacted

New electroactive asymmetrical chalcones and therefrom derived 2-amino- / 2-(1H-pyrrol-1-yl)pyrimidines, containing an N-[ω-(4-methoxyphenoxy)alkyl]carbazole fragment: synthesis, optical and electrochemical properties

• Daria G. Selivanova,
• Alexei A. Gorbunov,
• Olga A. Mayorova,
• Alexander N. Vasyanin,
• Igor V. Lunegov,
• Elena V. Shklyaeva and
• Georgii G. Abashev

Beilstein J. Org. Chem. 2017, 13, 1583–1595, doi:10.3762/bjoc.13.158

• ], Ullmann coupling [13][14], Buchwald–Hartwig amination [15] or N-alkylation of carbazole in the presence of alkali metal carbonates under MW irradiation [16]. In our case, the N-arylation was realized under phase transfer conditions using triethylbenzylammonium chloride (TEBA) as a catalyst [17][18

Nitration of 5,11-dihydroindolo[3,2-b]carbazoles and synthetic applications of their nitro-substituted derivatives

• Roman A. Irgashev,
• Nikita A. Kazin,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2017, 13, 1396–1406, doi:10.3762/bjoc.13.136

• of acetyl nitrate. Therefore, attempts to enhance yields of compounds 3 by using large amounts of acetyl nitrate have proved to be unsuccessful. Notably, 2,8-diamino-substituted ICZ derivatives have previously been prepared by using the Buchwald–Hartwig amination of the corresponding 2,8-dibromo-ICZs

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

• treatment of bipolar disorder and schizophrenia [10]. The process involves four reaction steps, one inline extraction, and a filtration step. The reaction is shown in Scheme 1. Initially, a Buchwald–Hartwig reaction is carried out between aryl iodide and aminothiazole. Pd2dba3 was used as a catalyst and

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• macrocycles by Pd-catalyzed Buchwald–Hartwig amination [36]. Though this method is often preferable for the macrocyclization in comparison to classical nucleophilic substitution [28][31], it is limited to bile acid derivatives bearing groups with C(sp2)–Hal bonds. In addition, the use of bile acid moieties

• anthraquinones. Further attempts to apply the Cu-based catalytic system in this reaction with L-proline and other commonly used N,N, N,O, and O,O bidentate ligands were fruitless. Previously, some of us successfully used the classic conditions of the Buchwald–Hartwig amination for the preparation of bis-amino

Facile synthesis of indolo[3,2-a]carbazoles via Pd-catalyzed twofold oxidative cyclization

• Chao Yang,
• Kai Lin,
• Lan Huang,
• Wei-dong Pan and
• Sheng Liu

Beilstein J. Org. Chem. 2016, 12, 2490–2494, doi:10.3762/bjoc.12.243

• designed sequence, it would allow us to establish a novel and simple route to indolo[3,2-a]carbazole derivatives. Our investigation started with the preparation of methyl 2,4-dianilinobenzoates (2a–e, Scheme 2). The double Buchwald–Hartwig coupling of methyl 2,4-dibromobenzoate 3 (obtained by treatment of

• Houpis protocol [15], Cu-catalyzed selective monoaminations of the 2,4-dibromobenzoic acid at the 2-position were achieved. After methyl esterification of ortho-aminated benzoic acids, substrates 4a and b were treated with other anilines under the previous Buchwald–Hartwig conditions to afford methyl 2,4

Catalytic Chan–Lam coupling using a ‘tube-in-tube’ reactor to deliver molecular oxygen as an oxidant

• Carl J. Mallia,
• Paul M. Burton,
• Alexander M. R. Smith,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1598–1607, doi:10.3762/bjoc.12.156

• improvements achieved with the Buchwald–Hartwig coupling, limitations such as sensitivity to air and moisture, functional group tolerance and the high cost of palladium, reignited the search for an improved method. In 1998, the groups of Chan [8], Evans [9] and Lam [10] independently reported upon mild methods

Half-sandwich nickel(II) complexes bearing 1,3-di(cycloalkyl)imidazol-2-ylidene ligands

• Johnathon Yau,
• Kaarel E. Hunt,
• Laura McDougall,
• Alan R. Kennedy and
• David J. Nelson

Beilstein J. Org. Chem. 2015, 11, 2171–2178, doi:10.3762/bjoc.11.235

• NHC·HCl salt, rendering these species highly accessible (Scheme 1b) [10]. After the initial work by Cowley and Jones, various other researchers have disclosed complexes of this form and tested them in cross-coupling reactions such as Buchwald–Hartwig amination [11], Suzuki–Miyaura cross-coupling [12], and

A facile synthetic route to benzimidazolium salts bearing bulky aromatic N-substituents

• Gabriele Grieco,
• Olivier Blacque and
• Heinz Berke

Beilstein J. Org. Chem. 2015, 11, 1656–1666, doi:10.3762/bjoc.11.182

• with the preparation of the N1,N2-di(pyridine-2-yl)benzen-1,2-diamine (8). The Buchwald–Hartwig amination was applied in the syntheses of 5 and 6 where 1,2-dichlorobenzene was coupled with aniline and 2,4,6-trimethylaniline, respectively (Scheme 1). Attempting the synthesis of the N1,N2-bis(2,6

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• inhibitor Gleevec [53][54][55]. Reported by the Innovative Technology Centre (ITC) in 2010, this landmark synthesis was realised as a continuous process featuring an amide formation, a nucleophilic substitution and a Buchwald–Hartwig coupling as key synthesis steps performed in flow (Scheme 4). Further

• application of this new concept was demonstrated in the flow synthesis of the atypical neurolepticum olanzapine (121) [104]. The synthesis begins with a Buchwald–Hartwig coupling between 2-iodonitrobenzene (122) and 2-aminothiophene 123 enabled by inductive heating (Scheme 21). After in-line extraction and

Tuning of tetrathiafulvalene properties: versatile synthesis of N-arylated monopyrrolotetrathiafulvalenes via Ullmann-type coupling reactions

• Vladimir A. Azov,
• Diana Janott,
• Dirk Schlüter and
• Matthias Zeller

Beilstein J. Org. Chem. 2015, 11, 860–868, doi:10.3762/bjoc.11.96

• excess cannot be considered a disadvantage of the method. Additionally, use of the inexpensive Cu(I) catalyst allows to avoid Buchwald–Hartwig amination [24][25], which employs more expensive Pd-based catalysts for a similar type of C–N coupling reactions. In a typical procedure, 1 equiv of MPTTF 7a, 7b

Redox active dendronized polystyrenes equipped with peripheral triarylamines

• Toshiki Nokami,
• Naoki Musya,
• Tatsuya Morofuji,
• Keiji Takeda,
• Masahiro Takumi,
• Akihiro Shimizu and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2014, 10, 3097–3103, doi:10.3762/bjoc.10.326

• examined before studying the functionalization of dendronized polystyrene. Thus, di(p-methoxyphenyl)amino groups were introduced to 4 using a Buchwald–Hartwig amination [11]. The choice of a base is crucial for this transformation, and the transformation was successfully carried out using Cs2CO3 as a base

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• wanted to use direct functionalization either via C–H activation or cross dehydrogenative coupling for C–C-bond-forming reactions avoiding the use of two prefunctionalized building blocks. Naturally, C–N-bond formation should proceed via Buchwald–Hartwig coupling. The target molecules can be considered

• -diarylindoles were successfully reacted with N-Boc-THIQ to furnish 1,2,3-trisubstituted indoles as target compounds. Furthermore, regioselective N-arylation of protected and unprotected 1-(indol-3-yl)-THIQs was successfully conducted using either simple iron or copper salts as catalysts. Keywords: Buchwald

• –Hartwig coupling; C–C coupling; C–H functionalization; iron catalysis; regioselective arylation; Introduction 1,2,3,4-Tetrahydroisoquinolines (THIQs) are common substructures in natural products [1]. The structural motif of 1-(indol-3-yl)-THIQ is also found in compounds with biological activity, for

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• prepared p-bromophenyl-substituted bicyclic 1,2-oxazine derivatives 12, 13, 15 and 16 provide options to perform cross-coupling reactions such as Buchwald/Hartwig, Heck, Hiyama, Kumada, Sonogashira or Stille couplings. In order to examine the conditions for Suzuki cross-couplings we subjected bicyclic

Visible light mediated intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes

• Theresa H. Nguyen,
• Soumitra Maity and
• Nan Zheng

Beilstein J. Org. Chem. 2014, 10, 975–980, doi:10.3762/bjoc.10.96

• -iodobenzene (19) and cycloproylamine, 2-bromo-N-cyclopropylaniline (20) was prepared in 75% yield via the Buchwald–Hartwig amination [39][40]. The [3 + 2] annulation of 2-bromo-N-cyclopropylaniline (20) and phenylacetylene (2) was performed using the optimized catalyst system to provide cyclic allylic amine

Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles

• Zong Guan,
• Jan C. Namyslo,
• Martin H. H. Drafz,
• Martin Nieger and
• Andreas Schmidt

Beilstein J. Org. Chem. 2014, 10, 832–840, doi:10.3762/bjoc.10.79

• available by copper-catalyzed aryl couplings or Buchwald–Hartwig reactions [22]. Pyrazol-3-ylidenes rearrange similarly to quinolines [17]. We report here on two unexpected rearrangements of indazol-3-ylidene, and trapping reactions of the N-heterocyclic carbene with rhodium. Results and Discussion On

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

Camera-enabled techniques for organic synthesis

• Steven V. Ley,
• Richard J. Ingham,
• Matthew O’Brien and
• Duncan L. Browne

Beilstein J. Org. Chem. 2013, 9, 1051–1072, doi:10.3762/bjoc.9.118

• is visible with the aid of the video camera; (d) a still from the footage showing arcing observed as a bright flash of light. Video stills reprinted from [47], Copyright 2008, with permission from Elsevier. (a) Buchwald–Hartwig coupling within a microchannel reactor. (b) Camera view of aggregate

Synthesis of 5-oxyquinoline derivatives for reversal of multidrug resistance

• Torsten Dittrich,
• Nils Hanekop,
• Nacera Infed,
• Lutz Schmitt and
• Manfred Braun

Beilstein J. Org. Chem. 2012, 8, 1700–1704, doi:10.3762/bjoc.8.193

• precursor 2c was obtained by an N-arylation, as described in the literature.[21] A modified Buchwald–Hartwig amination reaction using tri-tert-butylphosphane as a ligand at palladium [22] was applied in order to couple 4-methylphenyl bromide and 4-fluorophenyl bromide with Boc-protected aminopiperidines 17

Extending the utility of [Pd(NHC)(cinnamyl)Cl] precatalysts: Direct arylation of heterocycles

• Anthony R. Martin,
• Anthony Chartoire,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2012, 8, 1637–1643, doi:10.3762/bjoc.8.187

• ) (Figure 1). Complexes 1 and 2 are commercially available and have proven to be highly efficient in Suzuki–Miyaura coupling and Buchwald–Hartwig amination reactions [17][18][19][20]. We have also evaluated the recently reported [Pd(IPr*)(cin)Cl] (3), which has shown potency in Suzuki–Miyaura couplings [21

• ] and Buchwald–Hartwig N-arylations [22] even with challenging substrates. To complete this study and to examine the effect of bulky ligands about the metal centre, we have synthesised a new complex [Pd(IPr*Tol)(cin)Cl] (4), which is a IPr* congener. Results and Discussion The study begins with the

Double N-arylation reaction of polyhalogenated 4,4’-bipyridines. Expedious synthesis of functionalized 2,7-diazacarbazoles

• Mohamed Abboud,
• Emmanuel Aubert and
• Victor Mamane

Beilstein J. Org. Chem. 2012, 8, 253–258, doi:10.3762/bjoc.8.26

• system. Moderate to good yields were obtained in this site-selective Buchwald–Hartwig double amination. The functionalization of these tricyclic derivatives was performed by using Pd-catalyzed cross-coupling reactions such as the Stille and Suzuki couplings. Two compounds were analyzed by X-ray

• -diazacarbazole by using a palladium-catalyzed double N-arylation of 4,4’-dichloro-3,3’-bipyridine, itself obtained after a long reaction sequence [25][26][27]. In another patent, an intramolecular Buchwald–Hartwig amination [28][29] was used to generate a 2,7-diazacarbazole derivative in low yield [30]. Recently

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• preparation of various 2,3-disubstituted indole derivatives 62 (Scheme 27). Amines as coupling partners through Buchwald–Hartwig amination Other strategies used for the palladium-mediated three-component preparation of substituted indole derivatives involve an efficient Buchwald–Hartwig amination as the key

• coupling leading to a mono-alkynylated product, followed by an intermolecular Buchwald–Hartwig amination and a subsequent intramolecular amination. This Pd-catalyzed tandem coupling reaction allows the preparation of a variety of 2-alkynylindoles 64 (Scheme 28). An elegant three-component process based on

• transformations, including aza-Michael additions, hydroaminations of alkynes, Buchwald–Hartwig aminations, and allylic aminations, thereby allowing the creation of several covalent bonds in a single operation. Imine derivatives are also of high synthetic value as they may act either as electrophilic or

Translation of microwave methodology to continuous flow for the efficient synthesis of diaryl ethers via a base-mediated S_NAr reaction

• Charlotte Wiles and
• Paul Watts

Beilstein J. Org. Chem. 2011, 7, 1360–1371, doi:10.3762/bjoc.7.160

• ] (Figure 1). Installation of the diaryl ether can, however, be synthetically challenging, and this is illustrated by the wide number of techniques developed, which include Ullmann ether synthesis [6], Pummerer-type rearrangements [7], Buchwald–Hartwig couplings [8], phenolic additions to amines [9