A synthetic method that relies on gold(I)-catalyzed tandem 1,3-migration/[2 + 2] cycloaddition of 1,7-enyne benzoates to prepare azabicyclo[4.2.0]oct-5-enes is described.

This study describes the use of DNA functionalized gold nanoparticles (AuNPs) to enhance the synthesis of proteins in cell lysate and examines the mechanisms behind the enhanced mRNA translation. With an appropriate DNA oligomer sequence that hybridizes to the 3'-untranslated region of two mRNA of interest, insulin and green fluorescent protein (GFP), we found that these DNA conjugated AuNPs (AuNP-DNA) introduced into HeLa cell lysate enhanced the synthesis of insulin and GFP by up to 2.18 and 1.80-fold, respectively, over baseline production with just the mRNA present. The insulin synthesis was markedly reduced with non-DNA citrate-capped AuNP (1.25-fold) and AuNP-DNA with a nonspecific poly(T) sequence (1.25-fold). We showed that both nonspecific adsorption of ribosomes and translation factors to form a lysate protein corona on AuNP-DNA and weak hybridization between DNA oligomers and mRNA of interest were important factors that brought translation factors, ribosomes, and mRNA into close proximity of each other. This could reduce the recycling time of ribosomes during mRNA translation, thereby increasing the efficiency of protein synthesis. The outcome of this work shows that with rational DNA design, it could be possible to modulate intracellular biological processes with AuNP-DNA and increase their production of proteins for various biomedical applications.

ABSTRACT:A synthetic method to prepare tricyclic bridged heptenones and hexenones from gold(I)-catalyzed double cycloisomerization of 1,11-dien-3,9-diyne benzoates is described. A divergence in product selectivity was achieved by fine-tuning the steric nature of the ligand of the Au(I) catalyst. In the presence of [MeCNAu(JohnPhos)] + SbF6-(JohnPhos = (1,1'-biphenyl-2-yl)-ditert-butylphosphine) as the catalyst, tandem 1,3-acyloxy migration/metallo-Nazarov cyclization/1,6-enyne addition/Cope rearrangement of the substrate was found to selectively occur to afford the bridged heptenone adduct. In contrast, changing the Au(I) catalyst to [MeCNAu(Me4tBuXPhos)] + SbF6-(Me4tBuXPhos = di-tert-butyl(2',4',6'-triisopropyl-3,4,5,6-tetramethyl-[1,1'-biphenyl]-2-yl)phosphine) was observed to result in the 1,11-dien-3,9-diyne benzoate undergoing a more rapid tandem 1,3-acyloxy migration/metallo-Nazarov cyclization/[4 + 2]-cyclization pathway to give the bridged hexenone derivative.

A method to prepare (Z)-2-methylene-1-sulfonylindolin-3-ols efficiently that relies on silver acetate catalyzed hydroamination of 1-(2-(sulfonylamino)phenyl)prop-2-yn-1-ols is reported. The reactions proceed rapidly at room temperature with catalyst loadings as low as 1 mol % under conditions that did not require the exclusion of air or moisture. The utility of this N-heterocyclic ring-forming strategy as a synthetic tool that makes use of unsaturated alcohols was exemplified by the conversion of the (Z)-2-methylene-1-sulfonylindolin-3-ol to examples of other members of the indole family of compounds.

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. (2015) Gold-catalyzed cycloisomerization and Diels-Alder reaction of 1,4,9-Dienyne Esters to 3 a,6-Methanoisoindole Esters with pro-inflammatory cytokine antagonist activity. Chemistry -A European Journal, 21 (25 Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:"This is the peer reviewed version of the following Susanti, Dewi, Liu, Li-Juan, Rao, Weidong, Lin, Sheng, Ma, Dik-Lung, Leung, Chung-Hang and Chan, Philip Wai Hong. (2015) Goldcatalyzed cycloisomerization and Diels-Alder reaction of 1,4,9-Dienyne Esters to 3 a,6-Methanoisoindole Esters with pro-inflammatory cytokine antagonist activity. Chemistry -A European Journal, 21 (25). pp. 9111-9118. which has been published in final form at http://dx.doi.org/10.1002/chem.201500795 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving." A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. Abstract: A synthetic method to prepare 3a,6-methanoisoindole esters efficiently by gold(I)-catalyzed tandem 1,2-acyloxy migration/Nazarov cyclization followed by Diels-Alder reaction of 1,4,9-dienyne esters is described. We also report the ability of one example to inhibit binding of tumor necrosis factor- (TNF-) to the tumor necrosis factor receptor 1 (TNFR1) site and TNF--induced nuclear factor -light-chain-enhancer of activated B cells (NF-B) activation in cell at a half-maximal inhibitory concentration (IC50) value of 10 M. Along with this is a study showing the isoindolyl derivative to exhibit low toxicity toward human hepatocellular liver carcinoma (HepG2) cells and its possible mode of activity based on molecular modeling analysis.

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A synthetic method that relies on gold-catalysed cyclopropyl carbinol rearrangement of 2-tosylaminophenyl cyclopropylmethanols to prepare 2,3-dihydro-1H-benzo[b]azepines and 2-vinylindolines efficiently is reported. The reactions were shown to be chemoselective, with secondary and tertiary alcohol substrates exclusively providing benzo-fused five- and seven-membered ring products, respectively. The ring-forming process was also found to proceed in moderate to excellent yields under mild conditions only in the presence of the gold and silver catalyst combination. The mechanism is thought to involve activation of the alcohol by the (p-CF(3)C(6)H(4))(3)PAuCl/AgOTf (Tf = triflate) catalyst, resulting in ionization of the starting material. The tertiary carbocationic intermediate generated in situ in this manner then triggers ring-opening of the cyclopropane moiety and trapping by the tethered aniline group to give the 2,3-dihydro-1H-benzo[b]azepine. Cyclopropane ring fragmentation of the secondary carbocationic analogue, on the other hand, results in diene formation followed by subsequent intramolecular hydroamination to afford the 2-vinylindoline.