Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• substituents on the alkynes. The remarkable reactivity displayed by angle-strained alkynes makes them highly valuable tools in biorthogonal chemistry [107][108][109]. The reaction between dibenzo-fused cyclooctyne 20 and TCNE was observed to occur at room temperature, quantitatively yielding 22, wherein the

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• decrease in the yield [47]. Some research groups have utilized strain-promoted azide–alkyne cycloaddition reactions (SPAAC) on side chains to afford polymer-based prodrugs. Generally, a range of key strained cyclooctyne derivatives 52 could be reacted with aliphatic azides 51 via this strategy to give

• fully decorated triazoles 53 (Scheme 18a). A research group reported a novel polymer 56 functionalized by doxorubicin (DOX). To produce this prodrug, cyclooctyne-derivatized doxorubicin 55 was grafted on an azide-functionalized polymer 54. In the final step of the construction of this prodrug, the

Diaminoterephthalate–α-lipoic acid conjugates with fluorinated residues

• Leon Buschbeck,
• Aleksandra Markovic,
• Gunther Wittstock and
• Jens Christoffers

Beilstein J. Org. Chem. 2019, 15, 981–991, doi:10.3762/bjoc.15.96

• example for an application in biochemistry, Figure 1 shows a compound with cyclooctyne and maleimide as functional units. It was used as a "turn-on" fluorescence probe for cross-linking proteins [13]. The highly reactive cyclooctyne residue undergoes 1,3-dipolar cycloadditions with organoazides (copper

Dispersion-mediated steering of organic adsorbates on a precovered silicon surface

• Lisa Pecher,
• Sebastian Schmidt and
• Ralf Tonner

Beilstein J. Org. Chem. 2018, 14, 2715–2721, doi:10.3762/bjoc.14.249

• limiting factor regarding the packing of molecules. Here we show that the attractive part of the van der Waals potential can be similarly decisive. For the semiconductor surface Si(001), an already covalently bonded molecule of cyclooctyne steers a second incoming molecule via dispersion interactions onto

• the neighbouring adsorption site. This helps in understanding the nonstatistical pattern formation for this surface–adsorbate system and hints toward an inclusion of dispersion attraction as another determining factor for surface adsorption. Keywords: bonding analysis; cyclooctyne; density functional

• -defined surface chemistry without side reactions and lead to densely packed and well-ordered structures. Cyclooctyne (1), the smallest stable cyclic alkyne, on Si(001) is a system where this is the case and it has previously been thoroughly studied by experiment and theory [6][7][8]. Even though 1 is

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

• SPAAC in their one-pot stepwise preparation of GAuNPs, and then used those particles as supramolecular glycoprobes for the rapid serological recognition of a cancer biomarker. Firstly, ligand exchange was performed on Cit-AuNPs by reaction with a THF solution of a cyclooctyne disulfide and an aqueous

• ) conversion of these AuNPs into GAuNPs by CuAAC [74]. (a) Synthesis of the alkyne-terminated thiol (ATT) ligand 33; (b) synthesis of 12 nm sized ATT-AuNPs by ligand exchange. Synthesis of (a) cyclooctyne-functionalized AuNPs and (b) GAuNPs using SPAAC [82]. Supporting Information Supporting Information File

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• -workers [28]. AuNPs were firstly coated by a monolayer of dithiol-cyclooctyne spacer. Then, the alkyne moiety reacted with mannosyl azide through a copper-free strain-promoted alkyne-azide cycloaddition (SPAAC), affording the GAuNPs. Alternatively, Yan and co-workers developed a three-step photocoupling

• peanut agglutinin [25]. In this case, the glycosyl residue is not coated on the gold surface by means of a thiol moiety but exploiting the strain-promoted azide–alkyne cycloaddition (SPAAC) to covalently link an azido galactoside on a lipid cyclooctyne. In this manner, the amphiphilic glyco-lipid can be

• microscopy. The interaction among ConA-functionalized AuNPs (60 nm) and dextran-coated AuNPs (20 nm) are detected by DFM. Reprinted with permission from [50]. Copyright 2015 American Chemical Society. Copper-free cycloaddition (SPAAC) of azido galactoside on cyclooctyne and schematic depiction of Au surface

Learning from the unexpected in life and DNA self-assembly

• Jennifer M. Heemstra

Beilstein J. Org. Chem. 2015, 11, 2713–2720, doi:10.3762/bjoc.11.292

• to demonstrate this principle of split aptamer ligation, we functionalized one fragment of the cocaine-binding DNA split aptamer [8] with a cyclooctyne and the other fragment with an azide. Although the cyclooctyne and azide are inherently reactive towards one another [9], we hypothesized that in 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

• reactions are ideal for bioconjugation where no additional metal is required [31]. In 2012, Beal and co-workers incorporated the terminal alkyne and the activated cyclooctyne with two amide formation reactions [32], and then the SPAAC reaction was performed between the cyclooctyne 35 and the azides under

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

• Nicolas Desbois,
• Sandrine Pacquelet,
• Adrien Dubois,
• Clément Michelin and
• Claude P. Gros

Beilstein J. Org. Chem. 2015, 11, 2202–2208, doi:10.3762/bjoc.11.239

• ., cyclooctyne DOTA derivatives. Selected ligands for the copper(I)-catalyzed Huisgen cycloaddition. Structure of different bimetallic complexes 5–7. Synthesis of 8a,b and 9a–d. (i) for 8a: THF, N2, Cu(OAc)2·H2O, rt 15 min; for 8b: GaCl3 0.114 M in dry pyridine, reflux 1.5 h. (ii) for 9a: CHCl3/MeOH, Cu(OAc)2

Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

• Grzegorz Mlostoń,
• Paulina Grzelak,
• Maciej Mikina,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2015, 11, 576–582, doi:10.3762/bjoc.11.63

• studies [7][8]. Moreover, thiobenzophenone (1a) was reported to react as a heterodiene smoothly with cyclooctyne, dicyanoacetylene, and dimethyl acetylenedicarboxylate (2a) to give [4 + 2] cycloadducts of type 3a, which spontaneously rearrange via a 1,3-hydrogen shift yielding rearomatized products of

Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

• Andreas Gansäuer,
• Andreas Okkel,
• Lukas Schwach,
• Laura Wagner,
• Anja Selig and
• Aram Prokop

Beilstein J. Org. Chem. 2014, 10, 1630–1637, doi:10.3762/bjoc.10.169

• the synthesis of triazole-substituted titanocenes via strain-driven 1,3-dipolar cycloadditions between azide-functionalized titanocenes and cyclooctyne has been developed. It features the first synthesis of titanocenes containing azide groups. These compounds constitute ‘second-generation

• functionalization through the strain-driven 1,3-dipolar cycloaddition with cyclooctyne. The original conditions of Wittig [36], the reaction of cyclooctyne with phenyl azide, and the numerous applications pioneered by Bertozzi suggest that the reaction proceeds under mild conditions [34][35][37][38][39][40

• ]. Therefore, we simply mixed the titanocenes and cyclooctyne in CH2Cl2 at room temperature. The concentration of the substrates was intentionally kept low (0.1 M) to avoid a too intense evolution of heat. Typical examples of the reaction are summarized in Table 2. The results demonstrate that the strain

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

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

• [2.2]paracyclophanes. Unactivated triple bonds do not undergo cycloaddition (no reaction with tolane, 2-butyne, cyclooctyne, etc.). Switching to asymmetric triple-bond dienophiles, such as propiolic aldehyde (176), leads to a monosubstituted p-xylylene intermediate 177, which has four different options

Recent advances in the development of alkyne metathesis catalysts

• Xian Wu and
• Matthias Tamm

Beilstein J. Org. Chem. 2011, 7, 82–93, doi:10.3762/bjoc.7.12

• ]. The ROAMP of cyclooctyne (22) was performed using 5 and 6a as catalysts (Table 5) [78]. According to gel permeation chromatography (GPC) analysis, polymer parameters such as the molecular weight (Mn and Mw) and the polydispersity index (PDI) depend on the catalyst and substrate concentration, and the

• and 6b as catalysts. RCAM of 15 and 17 using 5 as catalyst. RCAM of 17b and 20 using 6a and 6b as catalysts. Ring-opening alkyne metathesis polymerization of cyclooctyne using 5 and 6a as catalysts. ACM of 33 using 29/MnCl2, 31 and 32/MnCl2 as catalysts. RCAM of 35 using 29/MnCl2, 31 and 32/MnCl2 as

Bioorthogonal metabolic glycoengineering of human larynx carcinoma (HEp-2) cells targeting sialic acid

• Arne Homann,
• Riaz-ul Qamar,
• Sevnur Serim,
• Petra Dersch and
• Jürgen Seibel

Beilstein J. Org. Chem. 2010, 6, No. 24, doi:10.3762/bjoc.6.24

• cyclooctyne (DIFO) and cell-surface azido-glycans introduced recently has been proven to be suitable for in vivo labelling [14][17][18]. Experimental 2-azidoacetylamino-2-deoxy-1,3,4,6-tetraacetyl-β-D-glucopyranoside (16) was synthesized as described previously [9] N-(1R,2R,3S,4R)-Hex-5-yonic acid (2,3,4,5