An amphiphilic pseudo[1]catenane: neutral guest-induced clouding point change

• Tomoki Ogoshi,
• Tomohiro Akutsu and
• Tada-aki Yamagishi

Beilstein J. Org. Chem. 2018, 14, 1937–1943, doi:10.3762/bjoc.14.167

• (CuAAC) ‘‘click’’ reaction (see details in the experimental section). In addition, model compound 4 was also synthesized as a reference (Figure 1d). Compound 3 is soluble in various organic and aqueous solvents as it comprises eight amphiphilic tri(ethylene oxide) chains. We investigated the

Synthesis and photophysical studies of a multivalent photoreactive Ru^II-calix[4]arene complex bearing RGD-containing cyclopentapeptides

• Sofia Kajouj,
• Lionel Marcelis,
• Alice Mattiuzzi,
• Adrien Grassin,
• Damien Dufour,
• Pierre Van Antwerpen,
• Didier Boturyn,
• Eric Defrancq,
• Mathieu Surin,
• Julien De Winter,
• Pascal Gerbaux,
• Ivan Jabin and
• Cécile Moucheron

Beilstein J. Org. Chem. 2018, 14, 1758–1768, doi:10.3762/bjoc.14.150

• anchoring i) of the photoreactive [Ru(TAP)2phen]2+ complex on the calix[4]arene small rim through a peptide-type coupling and ii) of the four c-[RGDfK] moieties on the opposite rim through a copper-catalyzed azide–alkyne cycloaddition (CuAAC) [66][67][68] (Figure 1). It was thus necessary to block the calix

• (CuAAC). Note that the triazole moieties that would result from such a cycloaddition are known to be stable towards hydrolysis and protease, which allows their use in a biological environment [72]. For the CuAAC, the use of CuI-generated in situ from a mixture of CuSO4·5H2O and sodium ascorbate is often

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• preliminary tests to assess their supramolecular absorption abilities towards a set of suitable organic guests, selected as pollutant models. The synthesis was accomplished by means of a CuAAC reaction between a tetrakis(propargyloxy)calix[4]arene and an alkyl diazide. The formation of the polymeric network

• extend and possibly improve the supramolecular binding abilities of CyNSs, mixed cyclodextrin-calixarene co-polymers nanosponges (CyCaNSs) were recently synthesized by exploiting a classical “click-chemistry” approach, namely the CuAAC reaction (Cu-catalyzed azide–alkyne cycloaddition [28][29][30

• number of azido groups present in the molecule. The actual accomplishment of the CuAAC reaction, and therefore the formation of the reticulated polymer network, was first assessed by means of FTIR spectroscopy. The FTIR spectra of the propargyloxycalixarene precursor Ca-OP, of the diazide A2 and the

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• ]. The synthesis of cryptands with C3 symmetry by peculiar reactions (acetylenic coupling [16][17][18], CuAAC [19][20][21][22], double or triple bond metathesis [23][24][25], aromatic nucleophilic substitutions [26][27][28][29][30][31][32][33], or via the amplification of a cryptand belonging to DCC

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• , in deuteric solvent hydrolyzed to give 3-deutero pyrazole. However, Fokin et al. has recently [123] revealed that monomeric copper acetylide complexes are not reactive toward organic azides in analogous copper-catalyzed alkyne–azide cycloaddition (CuAAC) and the catalysis by an external Cu(I) salt is

• necessary. This means that a dinuclear copper complex – most probably copper(I) acetylide bearing the π-bound copper salt – plays a key role during the cycloaddition step. On the basis of a crossover experiment with an isotopically enriched 63Cu(I) salt it was concluded that the CuAAC involves addition of

Novel unit B cryptophycin analogues as payloads for targeted therapy

• Eduard Figueras,
• Adina Borbély,
• Mohamed Ismail,
• Marcel Frese and
• Norbert Sewald

Beilstein J. Org. Chem. 2018, 14, 1281–1286, doi:10.3762/bjoc.14.109

• conjugation of the novel cryptophycin analogues across an appropriate linker to an antibody or peptide. Either a virtually uncleavable triazole (introduced by CuAAC) or scissile ester, carbonate, or carbamate moieties were taken into account. The synthesis of the modified unit B (Scheme 1) started with the

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• [19], copyright 2006 American Chemical Society. Ganciclovir. a) Custom-machined copper vessel and zirconia balls used to perform CuAAC reactions (showing: upper half of vessel with PTFE insert (front), pristine ZrO2 ball, used ZrO2 ball and lower half of vessel showing deformation of the metal). b

An uracil-linked hydroxyflavone probe for the recognition of ATP

• Márton Bojtár,
• Péter Zoltán Janzsó-Berend,
• Dávid Mester,
• Dóra Hessz,
• Mihály Kállay,
• Miklós Kubinyi and
• István Bitter

Beilstein J. Org. Chem. 2018, 14, 747–755, doi:10.3762/bjoc.14.63

• further stabilizes the complex, and this structure is energetically more favorable. These results prompted us towards the synthesis and evaluation of this promising molecule. Synthesis The synthesis of UHF is depicted in Scheme 1. UHF was synthesized by the CuAAC (click) reaction of 7-propargyloxy-3

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• ]. The versatility of the Cu(I)-catalysed azide–alkyne Huisgen cycloaddition (CuAAC) has been demonstrated by its robustness, insensitivity to water and oxygen, and its applicability to a wide range of substrates [42][43][44]. Although the AAC has been used by many groups to modify the surface of AuNPs

• synthesize peptide-decorated AuNPs [59] and nanomaterial hybrids containing single walled carbon nanotubes and AuNPs [60]. AuNP surface modification by CuAAC The distinct advantages of CuAAC over NCAAC, such as improved regioselectivity and rates of the reaction, motivated several groups to use CuAAC for the

• surface modification of AuNPs. In 2006, Brennan et al. demonstrated that enzyme–AuNP conjugates could be synthesized by CuAAC [47]. Azide-functionalized AuNPs were first synthesized by treating standard 14 nm Cit-AuNPs [28] with an a queous solution of an azide-containing thiol ligand (Scheme 7). An

Synthetic mRNA capping

• Fabian Muttach,
• Nils Muthmann and
• Andrea Rentmeister

Beilstein J. Org. Chem. 2017, 13, 2819–2832, doi:10.3762/bjoc.13.274

• dyes which could be applied as FRET pair. In this case, labeling was achieved in two bioorthogonal reactions, an iEDDA and a SPAAC reaction. Furthermore, dual modification with an azido and an alkyne function enabled fluorophore/biotin labeling using a combination of SPAAC and CuAAC reaction. Efficient

• , different hypermethylated cap analogues with a 2′-azido moiety allowed for reaction with an alkyne-modified RNA in a CuAAC reaction to yield cap modified RNA – albeit with a non-natural linkage (Figure 7A) [120]. This capping strategy also worked with an alkyne-modified triphosphorylated RNA and 5′-azido

• modified methylguanosine resulting in a capped RNA containing a triazole linkage after CuAAC reaction (Figure 7B) [121]. In a similar approach a 5′-azido-modified RNA was prepared by solid-phase synthesis and reacted with an alkyne-functionalized m7G-cap analogue in a CuAAC reaction [122]. Besides its

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• cycloaddition, CuAAC and RuAAC), the thiol–yne reaction, Diels–Alder reactions and the Sonogashira cross-coupling. While amino acids with a terminal alkyne in the side chain are well-known, the synthesis of their correlates where the carboxy group is replaced by a terminal alkyne is still tedious. Nevertheless

• -butylsulfinyl, R’ = Me, CHMe2, CH2CHMe2, cyclohexyl [17]. e,f) CuI or RuII-catalyzed [3 + 2] cycloadditions (CuAAC, RuAAC) [18][19][20][21]. e) R = Boc, R’ = Bn [19]. f) R = Boc, R’ = Me, CHMe2, CH2CHMe2, R’’ = Me, CHMe2, CH2Ph [21]. Two different approaches for the stereoselective de novo synthesis of

Synthesis, effect of substituents on the regiochemistry and equilibrium studies of tetrazolo[1,5-a]pyrimidine/2-azidopyrimidines

• Elisandra Scapin,
• Paulo R. S. Salbego,
• Caroline R. Bender,
• Alexandre R. Meyer,
• Anderson B. Pagliari,
• Tainára Orlando,
• Geórgia C. Zimmer,
• Clarissa P. Frizzo,
• Helio G. Bonacorso,
• Nilo Zanatta and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 2396–2407, doi:10.3762/bjoc.13.237

• reactions were planned between phenylacetylene and compounds 6a–c. The 1,2,3-triazole synthesis from the 1,3-dipolar cycloaddition reaction between 6a–c and terminal alkynes catalyzed by copper salts (CuAAC) [41][42][43] confirms that the reaction passes through an azide intermediate. In addition to mild

• reaction conditions and short reaction times, the advantage of CuAAC is the formation of 1,2,3-triazoles-1,4-disubstituted in a highly regioselective manner [41]. Recently, Cornec et al. [44] synthesized 4,6-dimethyl-2-(4-aryl-1H-1,2,3-triazol-1-yl)pyrimidines from azides using copper salts. The reaction

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• mechanochemical CuAAC reactions, indicating that the catalysis is most likely conducted on the surface of milling balls. Electron spin resonance spectroscopy was used to determine the oxidation and spin states of the respective copper catalysts in bulk products obtained by milling procedures. Keywords: electron

• spin resonance (ESR) spectroscopy; in situ Raman monitoring; mechanochemistry; quinoline; solid-state click chemistry; Introduction The copper-catalyzed azide–alkyne cycloaddition (CuAAC) represents a prime example of click chemistry. Click chemistry describes “a set of near-perfect” reactions [1] for

• it increases reaction rates and yields and directs the azide–alkyne cycloaddition exclusively towards 1,4-substituted regioisomers, whereas the non-catalyzed process results in a non-stoichiometric mixture of 1,4- and 1,5-regioisomers. Even though CuAAC reactions are efficiently performed in solution

BODIPY-based fluorescent liposomes with sesquiterpene lactone trilobolide

• Ludmila Škorpilová,
• Silvie Rimpelová,
• Michal Jurášek,
• Miloš Buděšínský,
• Jana Lokajová,
• Roman Effenberg,
• Petr Slepička,
• Tomáš Ruml,
• Eva Kmoníčková,
• Pavel B. Drašar and
• Zdeněk Wimmer

Beilstein J. Org. Chem. 2017, 13, 1316–1324, doi:10.3762/bjoc.13.128

• compound is shown in Scheme 1, part B. Propargyl-ChL [35] was introduced into Huisgen copper-catalyzed 1,3-dipolar cycloaddition [36] (CuAAC) with BODIPY 3. This microwave-assisted reaction catalyzed by CuSO4·5H2O, sodium ascorbate and a catalytic amount of TBTA (tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl

• -terminated intermediate 5 in excellent yield (92%). Finally, CuAAC cycloadition of 5 and Tb-N3VA [31] gave the target fluorescent construct 6 in good yield (84%). The absorbance and fluorescence emission spectra of compounds 3–6 are depicted in Figure 2. Compounds 3–6 showed absorption and emission maxima at

An eco-compatible strategy for the diversity-oriented synthesis of macrocycles exploiting carbohydrate-derived building blocks

• Sushil K. Maurya and
• Rohit Rana

Beilstein J. Org. Chem. 2017, 13, 1106–1118, doi:10.3762/bjoc.13.110

• the iterative use of readily available sugar-derived alkyne/azide–alkene building blocks coupled through copper catalyzed azide–alkyne cycloaddition (CuAAC) reaction followed by pairing of the linear cyclo-adduct using greener reaction conditions. The eco-compatibility, mild reaction conditions

• ] glycosides and macrocyclic glycolipids [11]. Similarly, the copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction has found wide application in medicinal chemistry [33], biology [34][35], polymer chemistry [36], carbohydrates [37][38][39][40], peptides [41][42][43][44] and in materials science [45][46

• ][47][48]. There are several reports wherein different strategies have been developed and used for the synthesis of glycoconjugates [9][49][50][51], however, the combination of a CuAAC and a RCM reaction has been used very little and rarely combinations of these reactions have been used for the

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• , synthesized from polymer 8 (Scheme 3) through Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) with the triethylene glycol linker 11 (N3-TEG-NH2) which had been prepared in a five-step procedure [62][63]. Probing multivalent interactions by AFM The adhesive forces of 12, due to supramolecular interactions

Energy down converting organic fluorophore functionalized mesoporous silica hybrids for monolith-coated light emitting diodes

• Markus Börgardts and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 768–778, doi:10.3762/bjoc.13.76

• functionalization can be achieved upon ligating a triethylsiloxy-functionalized azide and a terminal alkynyl-functionalized luminophore by CuAAC (Cu-catalyzed azide–alkyne cycloaddition) [21][22][23]. Commencing from a 2-hydroxy-substituted Nile red 1 or 3-hydroxymethylperylene (2) the alkyne-substituted

• were then reacted with azide 7 via CuAAC to furnish the triethoxysilyl-substituted luminophore precursor molecules 8 (red emission), 9 (blue emission), and 10 (green emission) (Scheme 1). In contrast to usually high yields of the CuAAC the precursor synthesis only gives yields between 44 to 45% after

Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction

• Qi An,
• Youssef Hassan,
• Xiaotong Yan,
• Peter Krolla-Sidenstein,
• Tawheed Mohammed,
• Mathias Lang,
• Stefan Bräse and
• Manuel Tsotsalas

Beilstein J. Org. Chem. 2017, 13, 558–563, doi:10.3762/bjoc.13.54

• solid liquid interfacial layer-by-layer (LbL) synthesis of CMP-nanomembranes via Cu catalyzed azide–alkyne cycloaddition (CuAAC). However, this process featured very long reaction times and limited scalability. Herein we present the synthesis of surface grown CMP thin films and nanomembranes via light

• catalyzed azide–alkyne cycloaddition (CuAAC) approach, respectively [16]. These procedures are still limited to conductive substrates or associated with long reaction times. In this work, we present a novel strategy for the LbL synthesis of CMP thin films and nanomembranes, using the light-induced and

• . The growth rate of roughly 1 nm per reaction cycle is in the same order as the previously described LbL synthesis of CMP nanomembranes using CuAAC click chemistry [16]. Synthesis of freestanding CMP nanomembranes In order to produce freestanding CMP nanomembranes, we coated the CMP thin films on

Investigation of the action of poly(ADP-ribose)-synthesising enzymes on NAD⁺ analogues

• Sarah Wallrodt,
• Edward L. Simpson and
• Andreas Marx

Beilstein J. Org. Chem. 2017, 13, 495–501, doi:10.3762/bjoc.13.49

• introducing small, terminal alkyne functionalities at common sites of the adenine base. Upon successful incorporation into PAR, these alkynes serve as handles for copper(I) catalysed azide–alkyne click reaction (CuAAC) [22] with fluorescent dyes. Terminal alkynes are the smallest possible reporter group that

• + analogue or a 1:1 mixture. Then, copper(I)-catalysed azide–alkyne click reaction (CuAAC) is performed and mixture is resolved by SDS PAGE. SDS PAGE analysis of ADP-ribosylation of histone H1.2 with ARTD1, ARTD2, ARTD5 and ARTD6 using NAD+ analogue 1. Upper panel shows Coomassie Blue staining; lower panel

A postsynthetically 2’-“clickable” uridine with arabino configuration and its application for fluorescent labeling and imaging of DNA

• Heidi-Kristin Walter,
• Bettina Olshausen,
• Ute Schepers and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2017, 13, 127–137, doi:10.3762/bjoc.13.16

• cells. Keywords: dyes; fluorescence; nucleic acid; oligonucleotide; Introduction The “click”-type reactions [1], in particular the 1,3-dipolar cycloaddition between alkynes and azides (CuAAC) is a broadly applied strategy for postsynthetic oligonucleotide modification since both reactive groups are

• only reaction rates but improves also regioselectivity. The formation of oligonucleotide oxidation side products by Cu(I) is avoided by the use of chelating Cu(I) ligands, in particular tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) and better water-soluble derivatives [9][10]. The CuAAC

• cannot only be applied for conventional postsynthetic oligonucleotide modification in solution but also on solid phase [11] and for the introduction of multiple postsynthetic modifications [12]. The azide groups for CuAAC are typically placed onto the fluorescent dyes since azides are not compatible with

Construction of bis-, tris- and tetrahydrazones by addition of azoalkenes to amines and ammonia

• Artem N. Semakin,
• Aleksandr O. Kokuev,
• Yulia V. Nelyubina,
• Alexey Yu. Sukhorukov,
• Petr A. Zhmurov,
• Sema L. Ioffe and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2016, 12, 2471–2477, doi:10.3762/bjoc.12.241

• on a support. This was demonstrated by the synthesis of a mixed triazole-hydrazone ligand 10 by CuAAC reaction of 3 with phenyl azide (Scheme 3) (for application of mixed triazole-imine ligands see [31][32][34]). Reaction of α-halogen-substituted hydrazones 1 with ammonia Addition of α-halohydrazones

Dinuclear thiazolylidene copper complex as highly active catalyst for azid–alkyne cycloadditions

• Anne L. Schöffler,
• Ata Makarem,
• Frank Rominger and
• Bernd F. Straub

Beilstein J. Org. Chem. 2016, 12, 1566–1572, doi:10.3762/bjoc.12.151

• cycloaddition (CuAAC) “click” reactions. The ancillary ligand comprises two 4,5-dimethyl-1,3-thiazol-2-ylidene units and an ethylene linker. The three-step preparation of the complex from commercially available starting compounds is more straightforward and cost-efficient than that of the previously described

• 1,2,4-triazol-5-ylidene derivatives. Kinetic experiments revealed its high catalytic CuAAC activity in organic solvents at room temperature. The activity increases upon addition of acetic acid, particularly for more acidic alkyne substrates. The modular catalyst design renders possible the exchange of N

• -heterocyclic carbene, linker, sacrificial ligand, and counter ion. Keywords: catalysis; click; copper; CuAAC; N-heterocyclic carbene; thiazole; Introduction The copper-catalyzed azide–alkyne cycloaddition (CuAAC) is one of the most important “click” reactions for the facile covalent linking of two molecules

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• “click-fleximer” as expanded nucleobase mimicking the purine [14]. “Click-fleximer” nucleoside analogues are easily accessible derivatives using copper-catalysed alkyne–azide cycloaddition (CuAAC) and this synthetic methodology allows generating a small library of derivatives depending on the nature of

• categories: aromatic alkynes with various substituents (methoxy, amino, formyl…) in ortho, meta or para position, and short alkyne chains such as 3-butyn-2-one or methylpropiolate. Starting from intermediate 2, the CuAAC reaction was either catalysed by CuI or CuSO4 (Table 1) and gave rise to the fully

• Information File 1). NMR studies To establish the stereochemistry and/or regiochemistry of the azidation and CuAAC steps, homo- or heteronuclear 2D NMR experiments (see Supporting Information File 2) were performed on compounds 2 and 3a (Figure 2). In addition, we synthesized compound 5 (resulting from an 1,5

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

• Svetlana V. Vasilyeva,
• Vyacheslav V. Filichev and
• Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

• experience, these reactions are not suitable for TINA-TFO derivatives due to excessive formation of side products. Copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) as a variation of the Huisgen 1,3-dipolar cycloaddition has become a widely used conjugation method in which the stereoselective formation

• of 1,2,3-triazoles can connect several components in one molecule [25][26]. CuAAC belongs to the class of chemical processes called “click-chemistry” and it is also a biorthogonal reaction because functional groups of natural biopolymers are not affected and do not participate in chemical

• for the synthesis of MGB-fluorophore and MGB-TFO conjugates via CuAAC (Figure 2). Properties of the conjugates obtained are discussed. Results and Discussion Synthesis of bifunctional linkers Two components in MGB-TFO conjugates must be connected by a linker, which is at least 12 chemical bonds long

Copper-catalyzed [3 + 2] cycloaddition of (phenylethynyl)di-p-tolylstibane with organic azides

• Mizuki Yamada,
• Mio Matsumura,
• Yuki Uchida,
• Masatoshi Kawahata,
• Yuki Murata,
• Naoki Kakusawa,
• Kentaro Yamaguchi and
• Shuji Yasuike

Beilstein J. Org. Chem. 2016, 12, 1309–1313, doi:10.3762/bjoc.12.123

• -disubstituted 1,2,3-triazoles. Since then, the CuAAC has been widely applied in organic synthesis [4][5][6][7][8][9][10][11][12], molecular biology [13][14][15][16][17], and materials science [18][19][20]. There are many reports of CuAACs by using terminal alkynes (including metal acetylides) [4][5][6][7][8][9

• ][10][11][12][13][14][15][16][17][18][19][20]. But the use of internal alkynes in CuAACs for the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles is a more challenging area because of the difficulty in regiocontrol based on the increased steric hindrance [21][22]. A regioselective CuAAC synthesis of

• been no reports concerning the synthesis of 1,4,5-trisubstituted 5-stibano-1,2,3-triazoles. Herein, we report a novel CuAAC of a simple alkynylstibane, (phenylethynyl)di-p-tolylstibane, with organic azides to form fully substituted 5-organostibano-1,2,3-triazoles. Results and Discussion We initially