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The precise and safe treatment of bioorthogonal prodrug system is hindered by separate administration of prodrug and its activator, which often results in poor therapeutic effects and severe side effects. To address above issues, we herein construct a single bioorthogonal-activated co-delivery system for simultaneous PROTAC prodrug (proPROTAC) delivery and controlled, site-specific activation for tumor-specific treatment. In this co-delivery system (termed AuPLs), prodrug (proPROTAC) and water-soluble Pd-catalyst are first encapsulated by gold nanocubes (AuNCs), which are further coated with a layer of phase-change material (lauric acid/stearic acid, LA/SA). Below 39 °C, the solid state of LA/SA prevents the activation of Pd-mediated bioorthogonal reaction due to the solidification of Pd-catalyst and proPROTAC. Nevertheless, once over 42 °C, the phase change of LA/SA into liquid state, enabled by the photothermal effect of AuNCs, triggers the simultaneous release of proPROTAC and Pd-catalyst and initiates the in situ bioorthogonal reaction for proPROTAC activation. In the tumor-bearing mouse models, the systemic administration of AuPLs results in the accumulation in tumor region, where the photothermal effect activates and controls the tumor-specific bioorthogonal reaction to degrade BRD4 protein, leading to anti-tumor effects with minimized side effects. Overall, the co-delivery proPROTAC and Pd-catalyst and controlled activation by photothermal effects provide a precise way for biorthogonal-based anticancer prodrugs., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aluminum is a very important analyte, and developing biosensors for aluminum is an important analytical task. In this work, we report a novel mechanism to design colorimetric sensor based on gold nanoparticles (AuNPs). The AuNPs were prepared by reducing HAuCl 4 using catechols, and the resulting AuNPs can be directly adapted for Al 3+ detection without any post-modifications, showing high sensitivity and selectivity against other metal ions. Interestingly, our mechanistic studies revealed that Al 3+ -induced AuNPs aggregation was not due to the formation of interparticle crosslinks that refers to the design principle of most AuNPs-based colorimetric sensors reported before. But rather, Al 3+ competitively coordinated with the capping ligands on AuNPs surface through the formation of stable Al-O bond, which dissociated these ligands from AuNPs surface. As a result, the AuNPs aggregated due to the loss of surface stabilizers. Based on this mechanism, several catechols, including pyrocatechol (PC), 3-(3,4-dihydroxyphenyl) propionic acid (DHCA), levodopa (LDA) and dopamine (DA), were used as reductant to prepare AuNPs for Al 3+ sensing, and the AuNPs prepared by DA (AuNPs/DA) displayed the highest sensitivity, with detection limit of 0.81 μM. The sensor was then tested for Al content analysis in river water and food samples, and the results supported its practical applications. Importantly, this work expands the design principles for colorimetric sensors by using AuNPs., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A new and convenient strategy for the synthesis of functionalized tropone derivatives based on the gold-catalyzed oxidative ring expansion of alkynyl quinols has been developed. The reaction proceeds via gold-catalyzed highly regioselective oxidation followed by 1,2-migration of a vinyl or phenyl group. Extension of this chemistry allows ready access to various seven- or six-membered ring systems such as benzotropones, benzooxepines, phenanthrenes, and quinolin-2(1H)-ones.

A gold-catalyzed cascade hydroamination/cyclization reaction of α-amino ketones with alkynes to form substituted pyrroles has been developed. The method offers several advantages such as high regioselectivity with the tested cases, wide functional group tolerance, and easily accessible starting materials. The synthetic utility of the obtained pyrrole products was demonstrated by their efficient transformations to 2-vinylated pyrroles via gold-catalyzed intermolecular hydroarylation.

Gold(I)-catalyzed regioselective cycloisomerizations of furan-ynes have been described. The reaction provides a concise access to stereodefined trisubstituted alkenes by endo cyclization with concomitant 1,5-migration of the furanyl group in the presence of unactivated 3 Å molecular sieves. In the absence of molecular sieves, indene products are generated by exo cyclization, followed by 1,4-furanyl migration/cyclization. The scope for 1,5-migrations can be extended to other heterocycles, such as benzofurans, thiophenes, and pyrroles., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Gold-catalyzed cascade cyclization/1,2-rearrangement of 1-(2-furanyl)phenyl propargyl alcohols has been developed, which provides a rapid and efficient access to multisubstituted 1-naphthols bearing an enal or enone moiety with high stereoselectivity. The (Z)- or (E)-stereochemistry can be easily controlled by choosing protected- or non-protected substrates. The utility of the methodology has been illustrated in the first total synthesis of wailupemycin G., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A gold-catalyzed cycloisomerization of silyl-protected 2-(1-alkynyl)-2-alken-1-(2-furanyl)-1-ols with various nucleophiles including water, alcohol, aniline, sulfonamide, and electron-rich arene has been developed. The method provides a highly efficient access to 5,7-disubstituted or 2,5,7-trisubstituted benzo[b]furans with a wide diversity of substituents under mild reaction conditions, which are not easily available by other methods. Remarkably, an interesting rearrangement of the alkyl group from C2 to the C3 position of the furan ring takes place during the cyclization process. The following gold-assisted allylic substitution enables an elaboration of benzo[b]furans on its side chain of the C5 position with a wide range of functional groups., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient and facile gold(I)-catalyzed one-pot cascade protocol has been developed for the synthesis of tryptamine-fused polycyclic privileged structures through the treatment of substituted tryptamines and 2-ethynylbenzoic acids or 2-ethynylphenylacetic acids. This strategy features the formation of one C-C bond and two C-N bonds with high yields and broad substrate tolerance. The selected reduced target molecules are validated to perform as α1-adrenergic receptors antagonists. The most potent one, 4bh, exhibits an IC50 value of 277 nM on α1A subtype with a selectivity ratio of 15.8 over α1B subtype.

A series of (E)-1-aryloxy-1-en-3-ynes has been prepared by Sonogashira coupling of 2-bromo-3-aryloxypropenoates with terminal alkynes using Pd(PPh(3))(4) and CuI as the catalysts in Et(3)N. The resulting enynyl-aryl ethers are found to be highly applicable to the synthesis of 2,4-disubstituted furans with an ester group at C-4 position through an Au/Ag-catalyzed annulation reaction under extremely mild reaction conditions., (This journal is © The Royal Society of Chemistry 2012)

The gold(I)-catalyzed intramolecular cycloisomerization of furan/ynes bearing a silyloxy or allyloxy group has been developed, which provides a highly efficient access to protected 1-naphthol derivatives with enal or enone moiety. The method offers several advantages such as high stereoselectivities, mild reaction conditions, and easily accessible starting materials. In addition, the naphthyl products could be further transformed into the important benzocoumarins in a one-pot procedure.

The gold-catalyzed tandem cyclization of 1,2-bis(alkynyl)-2-en-1-ones with indoles offers an efficient and straightforward route to indole-fused polycyclic systems. The process is realized through a cascade carbonyl-yne cyclization/Friedel-Crafts/indole-yne cyclization sequence catalyzed by a single-pot catalyst of gold.

An efficient access to N-phth pyrrroles via gold-catalyzed cycloisomerization of N-phth alkynylaziridines has been described. Functionalized pyrroles including pyrrole-2-carboxylates or 2-pyrrolyl ketone are easily constructed in generally good yields by this method. The resulting pyrroles can be further converted to N-amino pyrrole or 2-acyl pyrrole, which are important synthetic intermediates for amplification of molecular complexity.

A gold‐catalyzed cyclization/cascade skeletal rearrangement of o‐cyanophenylalkynones with 3‐amino‐benzo[d]‐isoxazoles has been developed, which provides an approach for synthesizing medium‐sized benzolactones. Based on the experimental results, we postulate that the initial nucleophilic attack occurs preferentially at the keto moiety instead of the gold‐carbene. This reactivity initiates an attractive cascade process involving carbene transfer, 1,2‐aryl migration, cycloaddition, ring‐expansion etc. resulting in multiple bonds cleavage of the initial substrates. [ABSTRACT FROM AUTHOR]

A gold-catalyzed oxidative cyclization of alkyne–nitriles using water or alcohol as the external nucleophiles has been developed. The catalytic system, featured with gold and Lewis acid dual catalysis, allows a facile synthesis of functionalized isoquinolin-1(2H)-ones and 1-alkoxy-isoquinolines with a wide structural diversity. [ABSTRACT FROM AUTHOR]

A new and efficient method for the synthesis of unsymmetrical 1,3-butadiynes by gold-catalyzed C(sp)-C(sp) cross-coupling of terminal alkynes with alkynyl hypervalent iodine(III) reagents has been developed. The reaction features high selectivity and efficiency, mild reaction conditions, wide substrate scope, and functional-group compatibility, and is a highly attractive complement to existing methods. Mechanistic studies reveal that formation of a phenanthrolinyl-ligated gold(I) complex is crucial for the efficiency and selectivity of the target transformation. [ABSTRACT FROM AUTHOR]

Gold-catalyzed cascade cyclization/1,2-rearrangement of 1-(2-furanyl)phenyl propargyl alcohols has been developed, which provides a rapid and efficient access to multisubstituted 1-naphthols bearing an enal or enone moiety with high stereoselectivity. The (Z)- or (E)- stereochemistry can be easily controlled by choosing protected- or non-protected substrates. The utility of the methodology has been illustrated in the first total synthesis of wailupemycin G. [ABSTRACT FROM AUTHOR]

A gold-catalyzed cycloisomerization of silyl-protected 2-(1-alkynyl)-2-alken-1-(2-furanyl)-1-ols with various nucleophiles including water, alcohol, aniline, sulfonamide, and electron-rich arene has been developed. The method provides a highly efficient access to 5,7-disubstituted or 2,5,7-trisubstituted benzo[ b]furans with a wide diversity of substituents under mild reaction conditions, which are not easily available by other methods. Remarkably, an interesting rearrangement of the alkyl group from C2 to the C3 position of the furan ring takes place during the cyclization process. The following gold-assisted allylic substitution enables an elaboration of benzo[ b]furans on its side chain of the C5 position with a wide range of functional groups. [ABSTRACT FROM AUTHOR]

Wohin wandert das Acyl? Eine Gold ‐ katalysierte Umwandlung von α ‐ (2 ‐ Indolyl)propargylalkoholen mit Iminen in Gegenwart des Oxidationsmittels 8 ‐ Isopropylchinolin ‐ N ‐ oxid bietet schnellen Zugang zu hoch funktionalisierten Dihydro ‐ γ ‐ carbolinen (siehe Schema). Der Reaktionsmechanismus umfasst den intermolekularen Abfang eines intermediären α ‐ Carbonylgoldcarbenoids mit anschließender Cyclisierung und einer neuartigen Gold ‐ vermittelten 1,2 ‐ Acylwanderung. [ABSTRACT FROM AUTHOR]

The article presents chemical equations related to the gold-catalyzed Cascade Reactions of Furan-ynes with external nucleophiles with straightforward synthesis of multi-substituted benzo[b]furans" by N. Sun and others, published in the periodical "Chemistry - A European Journal" in 2014.

Abstract: An attractive method for assembling π-conjugated dienynes with high stereoselectivity was achieved by dehydration reaction of TMS-substituted [3]cumulenols catalyzed by TsOH·H2O. On the other hand, cycloisomerizations of the corresponding [3]cumulenones catalyzed by gold(I) complexes afford vinyl furans through activation of the cumulenic double bond via a π-complex, and during the process, deprotonation from an alkyl group on cumulene terminus takes place to induce the isomerization. [Copyright &y& Elsevier]