A semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J based on the spinosyn A aglycone

• Kai Zhang,
• Shenglan Liu,
• Anjun Liu,
• Hongxin Chai,
• Jiarong Li and
• Lamusi A

Beilstein J. Org. Chem. 2017, 13, 2603–2609, doi:10.3762/bjoc.13.257

• semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J based on spinosyn A with high yields in each step. With this synthetic route, we achieved a chemoselective hydrogenation of the 5,6-double bond under mild conditions, which is of great significance for future studies on the chemical modification of spinosyns

A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway

• Dmitry Yu. Vandyshev,
• Khidmet S. Shikhaliev,
• Andrey Yu. Potapov,
• Michael Yu. Krysin,
• Fedor I. Zubkov and
• Lyudmila V. Sapronova

Beilstein J. Org. Chem. 2017, 13, 2561–2568, doi:10.3762/bjoc.13.252

• multiplet (3.17–3.25 ppm). The addition of trifluoroacetic acid did not have a significant effect on the position of the signals of these protons. Thus, the reaction of itaconimides 1 with diaminoimidazole 4 is a regioselective and chemoselective cascade process involving an initial C-addition of

• the HPLC–HRESIMS monitoring of the reaction confirm its selectivity. Conclusion In summary, a new regioselective and chemoselective cascade reaction of N-arylitaconimides with 1,2-diamino-4-phenylimidazole as 1,3-C,N-dinucleophile was developed to synthesize tetrahydroimidazo[1,5-b]pyridazines. The

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• as sulfate esters and deoxy glycosides have been successfully synthesized. The preactivation-based chemoselective glycosylation is a powerful strategy for oligosaccharide assembly complementing the more traditional premixed method. Keywords: chemoselectivity; glycosides; preactivation; synthesis

• the type of glycosyl donors that can undergo a preactivation-based chemoselective glycosylation with an emphasis on thioglycosides due to their wide applicability. Preactivation of glycosyl sulfoxides: early success of preactivation One of the earliest preactivation-based glycosylation reactions

• oligosaccharides. Chemoselective dehydrative glycosylation with glycosyl hemiacetals Most glycosylation reactions require a functionalization of the anomeric position of a glycosyl donor followed by the reaction with a promoter to induce the irreversible transfer of the donor to an acceptor [31][32][33][34][35

Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes

• Hao Wang,
• Cui Chen,
• Weibing Liu and
• Zhibo Zhu

Beilstein J. Org. Chem. 2017, 13, 2023–2027, doi:10.3762/bjoc.13.200

• feedstocks and organic molecules, owing to their potential for extensive application in organic syntheses. Approaches for the efficient, regio- and chemoselective difunctionalization of alkenes have been developed that are attractive for rapidly building complex difunctionalized molecules from simple

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

• ). However, NCS-cericammonium nitrate (CAN) successfully yielded mono-chlorinated products [88]. Consecutively, the same group reported metal-free oxidative iodination of electron rich aromatic rings with molecular iodine and oxone (Scheme 25) [98]. This method proved to be highly chemoselective and no

An improved preparation of phorbol from croton oil

• Alberto Pagani,
• Simone Gaeta,
• Andrei I. Savchenko,
• Craig M. Williams and
• Giovanni Appendino

Beilstein J. Org. Chem. 2017, 13, 1361–1367, doi:10.3762/bjoc.13.133

• activity. While efficient chemoselective esterification protocols have been developed for phorbol, its isolation from croton oil is technically complicated, and involves extensive manipulation of very toxic materials like the oil or its native diterpenoid fraction. Results: The preparation of a crude non

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• -glucose in the presence of HCl to provide the methyl glycoside (pathway a, Scheme 6). The reaction proceeds chemoselective at the anomeric position. More recent examples typically use Lewis acids [29][30][31][32][33][34] or microwave irradiation [35][36] to accelerate the reaction. However, shortcomings

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