Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• group and the sulfonylimine. One way to achieve this could be in the chemoselective reduction of the C=N group of oxoimide 3, addition of the alkynyl moiety to the carbonyl group, and re-oxidation of the sultam to the sulfonimide (see Scheme 4). There are a number of reductions of oxoimide 3 reported in

Chemoselective synthesis of diaryl disulfides via a visible light-mediated coupling of arenediazonium tetrafluoroborates and CS₂

• Jing Leng,
• Shi-Meng Wang and
• Hua-Li Qin

Beilstein J. Org. Chem. 2017, 13, 903–909, doi:10.3762/bjoc.13.91

• Jing Leng Shi-Meng Wang Hua-Li Qin School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430070, PR China 10.3762/bjoc.13.91 Abstract A highly efficient and chemoselective method for the synthesis of diaryl disulfides is developed via a

• -mediated coupling of arenediazonium tetrafluoroborates and CS2 for the chemoselective assembly of diaryl disulfides as our continuing endeavor of utilizing arenediazonium tetrafluoroborates [16] for synthetic applications (Scheme 1). We conducted our initial study with benzenediazonium tetrafluoroborate

• disulfides. Further studies to clearly understand the reaction mechanism and the synthetic applications are ongoing in our laboratory. Chemoselective assembly of diaryl disulfides. A plausible reaction mechanism. Solvent screening for the coupling of benzenediazonium tetrafluoroborate (1a) and CS2 (2).a

A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

• Arno Verlee,
• Thomas Heugebaert,
• Tom van der Meer,
• Pavel I. Kerchev,
• Frank Van Breusegem and
• Christian V. Stevens

Beilstein J. Org. Chem. 2017, 13, 303–312, doi:10.3762/bjoc.13.33

• known for their bioactivity, a chemoselective procedure has been developed starting from m-(chlorosulfonyl)benzoyl chloride. Although a chemoselective process in batch was already reported, a continuous-flow process reveals an increased selectivity at higher temperatures and without catalysts. In total

• , 15 analogues were synthesized, using similar conditions, with yields ranging between 65 and 99%. This is the first automated and chemoselective synthesis of m-sulfamoylbenzamide analogues. Keywords: flow chemistry; medium-throughput synthesis; m-sulfamoylbenzamide analogues; Introduction Small

• ) aggregation [14], which is a major cause of neurodegeneration in Huntington’s disease. Although there are numerous reports available on the study of these analogues, an automated, chemoselective alternative to the synthesis is not yet available. The most common synthetic approach starts from m-(chlorosulfonyl

Chromium(II)-catalyzed enantioselective arylation of ketones

• Gang Wang,
• Shutao Sun,
• Ying Mao,
• Zhiyu Xie and
• Lei Liu

Beilstein J. Org. Chem. 2016, 12, 2771–2775, doi:10.3762/bjoc.12.275

• pharmaceutical industry. The chromium (Cr)-catalyzed enantioselective addition of carbo halides to carbonyl compounds is one of the most reliable methods in organic chemistry for chemoselective and structurally diverse synthesis [1][2][3][4][5][6][7][8][9]. To date, the Cr-catalyzed enantioselective carbonyl

Electron-transfer-initiated benzoin- and Stetter-like reactions in packed-bed reactors for process intensification

• Anna Zaghi,
• Daniele Ragno,
• Graziano Di Carmine,
• Carmela De Risi,
• Olga Bortolini,
• Pier Paolo Giovannini,
• Giancarlo Fantin and
• Alessandro Massi

Beilstein J. Org. Chem. 2016, 12, 2719–2730, doi:10.3762/bjoc.12.268

• columns) have been fabricated and operated to accomplish the chemoselective synthesis of aroylated α-hydroxy ketones and 2-benzoyl-1,4-diones (benzoin- and Stetter-like products, respectively) with a good level of efficiency and with a long-term stability of the packing material (up to five days

• umpolung of aromatic α-diketones and demonstrated its efficacy in the chemoselective synthesis of benzoin- and Stetter-like products (aroylated α-hydroxy ketones and 2-benzoyl-1,4-diones, respectively) through the operation of fixed-bed reactors packed with a readily and commercially available polymer

Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid

• Federica Santoro,
• Matteo Mariani,
• Federica Zaccheria,
• Rinaldo Psaro and
• Nicoletta Ravasio

Beilstein J. Org. Chem. 2016, 12, 2627–2635, doi:10.3762/bjoc.12.259

• a maximum yield of 83% and it can be used only for primary benzylic alcohols. On the contrary Ni nanoparticles act as chemoselective catalysts at room temperature [20]. 1,3,5-Triazo-2,4,6-triphosphorine-2,2,4,4,6,6-hexachloride (TAPC) allows the efficient preparation of thioethers from different

Inhibition of peptide aggregation by means of enzymatic phosphorylation

• Kristin Folmert,
• Malgorzata Broncel,
• Hans v. Berlepsch,
• Christopher H. Ullrich,
• Mary-Ann Siegert and
• Beate Koksch

Beilstein J. Org. Chem. 2016, 12, 2462–2470, doi:10.3762/bjoc.12.240

• characteristics, outstanding stability, regular fibrous architecture and high synthetic accessibility with numerous chemoselective ligation and modification methods [24][25][26]. Also, various post-translational modifications, like phosphorylation or glycosylation have been studied as aggregation triggers [27][28

Rapid regio- and multi-coupling reactivity of 2,3-dibromobenzofurans with atom-economic triarylbismuths under palladium catalysis

• Maddali L. N. Rao,
• Jalindar B. Talode and
• Venneti N. Murty

Beilstein J. Org. Chem. 2016, 12, 2065–2076, doi:10.3762/bjoc.12.195

• Maddali L. N. Rao Jalindar B. Talode Venneti N. Murty Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, U.P., India, Tel/ Fax: +91-512-2597532 10.3762/bjoc.12.195 Abstract A regio- and chemoselective cross-coupling study using 2,3-dibromobenzofurans and 2,3,5

• 2,3-dibromo-5-nitrobenzofuran (1.2) furnished the corresponding 2-aryl-3-bromobenzofurans 2.13–2.15 in 76–88% yields (Table 2, entries 13–15). Additionally, we have also planned chemoselective couplings with differently functionalized 2,3-dibromobenzofurans. This study using 2,3-dibromobenzofurans

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

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• 7TJ, UK 10.3762/bjoc.12.103 Abstract Here we report the chemoselective synthesis of several important, climate relevant isoprene nitrates using silver nitrate to mediate a ’halide for nitrate’ substitution. Employing readily available starting materials, reagents and Horner–Wadsworth–Emmons chemistry

• which [41][42][43] possessing a chemically differentiated C=C bond (appended at one end with a chloromethylene and the opposing end an ester) should allow the chemoselective reduction of the ester to the corresponding 1° alcohol. This we predicted would allow, depending on the starting material employed

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

• Bamford–Stevens-like transformation, the reaction with the adjacent alkyne proved to be much faster to provide the bridged-polycyclic product 89. The conditions employed were sufficiently mild and chemoselective that the epoxide in cyclohexane 91 remained intact in the reaction to form 92. The use of

Gold-catalyzed direct alkynylation of tryptophan in peptides using TIPS-EBX

• Gergely L. Tolnai,
• Jonathan P. Brand and
• Jerome Waser

Beilstein J. Org. Chem. 2016, 12, 745–749, doi:10.3762/bjoc.12.74

• instantaneous. It was highly chemoselective for thiols in the presence of other nucleophilic functional groups. The alkynylation could be therefore applied to cysteine-containing peptides. The scope of the reaction could be later extended to a broad range of aliphatic and aromatic alkynes [35]. In 2015, the

Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions

• Rajeev S. Menon,
• Akkattu T. Biju and
• Vijay Nair

Beilstein J. Org. Chem. 2016, 12, 444–461, doi:10.3762/bjoc.12.47

• ). The NHC-catalysed chemoselective intermolecular cross-benzoin condensation reaction of aromatic and aliphatic aldehydes was reported by Yang and co-workers. The chemoselectivity was achieved by using a large excess of the aliphatic aldehyde (molar ratio of 1:15) [25]. Thus, directing groups on the

• trifluoromethyl ketones were later developed using the chiral catalyst 27 (Scheme 13) [29]. The electron-deficient triazolium-derived NHC 23 mediated efficient and chemoselective cross-benzoin reactions of aldehydes and α-ketoesters to produce acyloin products endowed with a quaternary stereocentre [30

• yields (Scheme 14). Interestingly, preliminary experiments to develop an enantioselective version of this reaction using a chiral NHC returned promising levels of enantioselectivity (76% ee). Subsequently, Gravel and co-workers reported a high yielding chemoselective and enantioselective intermolecular

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

• Hans Sterckx,
• Johan De Houwer,
• Carl Mensch,
• Wouter Herrebout,
• Kourosch Abbaspour Tehrani and
• Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

• anilines resulting in the formation of 2-aryl-α-ketoacetamides was reported by Jiao [22] and a closely related intramolecular variant leading to isatins has been published by Ilangovan [23]. A remarkable Cu-catalyzed chemoselective oxidative C–C bond cleavage of methyl ketones was reported by the group of

• reactive alkyl-substituted pyridines. Gao showed that NH4I can also be used as an organocatalyst in combination with AcOH to facilitate the oxidation of benzylpyridines to benzoylpyridines [29]. Satoh and Miura showed that when replacing O2 for Na2S2O8 chemoselective methylenation occurred over oxygenation

• metabolites is therefore of great importance to facilitate the drug discovery process [42]. For this purpose chemoselective oxidation protocols are a valuable tool since they can provide us with metabolites typically generated by cytochrome P450 enzymes. Bearing this in mind we attempted to oxygenate the

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

• Zhan-Jiang Zheng,
• Ding Wang,
• Zheng Xu and
• Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

• -bistriazoles. The sequential, chemoselective preparation of bistriazoles. The sequential SPAAC and CuAAC reaction for the preparation of bistriazoles. The synthesis of D-mannitol-based bistriazoles. The synthesis of ester-linked and amide-linked bistriazoles. The synthesis of acenothiadiazole-based

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms

• Tatjana Huber,
• Lara Weisheit and
• Thomas Magauer

Beilstein J. Org. Chem. 2015, 11, 2521–2539, doi:10.3762/bjoc.11.273

• three steps enabled preparation of the annulation precursor 121. The following Pauson–Khand reaction [61] for the construction of the fused bicyclic structure 122 was performed by treatment of 121 with dicobaltoctacarbonyl in the presence of cyclohexylamine. Hydrolysis of the acetonide, chemoselective

Versatile synthesis and biological evaluation of novel 3’-fluorinated purine nucleosides

• Hang Ren,
• Haoyun An,
• Paul J. Hatala,
• William C. Stevens Jr,
• Jingchao Tao and
• Baicheng He

Beilstein J. Org. Chem. 2015, 11, 2509–2520, doi:10.3762/bjoc.11.272

• broad biological space for this class of nucleoside derivatives. The 2,6-dichloropurine (41) was glycosylated with the 3’-fluororibose intermediate 25 to furnish the 2,6-dichloropurine intermediate 42 in 89% yield (Scheme 4). Chemoselective amination of the 6-position over the 2-position of the purine

Beyond catalyst deactivation: cross-metathesis involving olefins containing N-heteroaromatics

• Kevin Lafaye,
• Cyril Bosset,
• Lionel Nicolas,
• Amandine Guérinot and
• Janine Cossy

Beilstein J. Org. Chem. 2015, 11, 2223–2241, doi:10.3762/bjoc.11.241

• of the reasons of this success is the discovery of well-defined, stable, highly chemoselective and now commercially available catalysts particularly the Grubbs catalysts 1st and 2nd generation (GI and GII) and the Grubbs–Hoveyda II catalyst (G-HII) (Figure 1) [13]. A large array of functional groups

Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp²)–H bond arylations

• Fatiha Abdelmalek,
• Fazia Derridj,
• Safia Djebbar,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2015, 11, 2012–2020, doi:10.3762/bjoc.11.218

• very chemoselective, as the reactions only involve desulfitative coupling even in the presence of C–halogen bonds [57], which allow further orthogonal transformations. Moreover, a wide scope of benzenesulfonyl chlorides is commercially available at an affordable cost. We report herein, a new synthetic

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• dimerized 16-membered ring product 101 in 57% yield, which was generated by a RRM–dimerization sequence and its monomer 100 in 14% yield along with 99 in 26% yield (Scheme 20). Bicyclo[2.2.1]heptene derivatives Holtsclaw and Koreeda [25] have explored a chemoselective RRM of the enone containing norbornene

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

• pharmaceutical. For this endeavour dihydroartimisinic acid (56), an advanced building block that is available via chemoselective batch reduction of bioengineered artemisinic acid (57), was chosen as the starting point. The key transformations to yield artemisinin thus demanded a reaction cascade including a

Cathodic hydrodimerization of nitroolefins

• Michael Weßling and
• Hans J. Schäfer

Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131

• applied. The reaction is chemoselective as only the double bond but not the nitro group undergoes reaction, is regioselective as a ß,ß-coupling with regard to the nitro group and forms preferentially two out of six possible diastereomers as major products. Keywords: cathodic hydrodimerization; C–C bond

• different 1-aryl and mostly 2-methyl substituents. Likewise the cathodic cyclization of a dinitrodiene could be realized. The dimerization is chemoselective: the fairly easy reduction of the nitro group can be suppressed and aryl C–Cl and aryl C–F bonds are not cleaved. Additionally a good regioselectivity

Regioselective synthesis of chiral dimethyl-bis(ethylenedithio)tetrathiafulvalene sulfones

• Flavia Pop and
• Narcis Avarvari

Beilstein J. Org. Chem. 2015, 11, 1105–1111, doi:10.3762/bjoc.11.124

• -dibromoethane to afford the chiral monosulfones (S,S)-1 and (R,R)-1. Thus, the oxidation of one of the outer sulfur atoms takes place in situ as the intermediate DM-EDT-TTF dithiolates are reactive towards oxygen. Interestingly, the reaction is regio- and chemoselective, as only compound 1 was isolated after

Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

• Antonio Monopoli,
• Pietro Cotugno,
• Carlo G. Zambonin,
• Francesco Ciminale and
• Angelo Nacci

Beilstein J. Org. Chem. 2015, 11, 994–999, doi:10.3762/bjoc.11.111

• -2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji–Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst

• chemoselective, but occurs under very mild temperature conditions and the operating procedure is further simplified employing the catalyst prepared in situ. In addition, benzothiazol-2-ylidene ligands proved to be not only more efficient in terms of selectivity than the toxic phosphanes but can compete

Orthogonal dual-modification of proteins for the engineering of multivalent protein scaffolds

• Michaela Mühlberg,
• Michael G. Hoesl,
• Christian Kuehne,
• Jens Dernedde,
• Nediljko Budisa and
• Christian P. R. Hackenberger

Beilstein J. Org. Chem. 2015, 11, 784–791, doi:10.3762/bjoc.11.88

• use of chemical labeling methods to study structure and function of proteins in vitro and in vivo, chemoselective conjugation techniques are also used to functionalize artificial protein scaffolds, such as viral capsids [5][6][7]. Such templates have self-assembled hierarchical structures that allow

• engineer multivalent glycoprotein conjugates, we have used the incorporation of non-canonical amino acids (NCAA) [13] by supplementation based incorporation (SPI) [14][15][16][17] in auxotroph expression systems followed by the chemoselective Cu-catalyzed azide–alkyne cycloaddition (CuAAC) to attach

• carbohydrate ligands to the protein barstar [18]. In the current study, we aimed to extend this approach to the dual modification of proteins using a combination of two chemoselective, orthogonal conjugation reactions for the introduction of glycan ligands and biotin to a protein. Our main objective in this