The glycan plays an important role in cellular recognition in living system by utilizing “cluster effect” and “pattern recognition”. In order to understand the structure-function relationship of ...glycan to a full extent, the mimicry of these effects by chemical method is in demand. We combined the strain-promoted alkyne-azide cycloaddition and our original RIKEN click reaction to synthesize homogeneous and heterogeneous glycocluster chemically on the albumin template. With these glycoclusters, specific cellular recognition could be achieved both in vitro and in vivo, depending on the lectin expression on the target cells. We also accomplished the first organ-selective metal-catalyzed organic reaction in living animal using the glycocluster system.
In organic chemistry, selecting mild conditions for transformations and saving energy are increasingly important for achieving sustainable development goals. Herein, we describe a red-light-mediated ...Barton decarboxylation using readily available red-light-emitting diodes as the energy source and zinc tetraphenylporphyrin as the catalyst, avoiding explosive or hazardous reagents or external heating. Mechanistic studies suggest that the reaction probably proceeds
via
Dexter energy transfer between the activated catalyst and the Barton ester. Furthermore, a one-pot wavelength-selective reaction within the visible light range is developed in combination with a blue-light-mediated photoredox reaction, demonstrating the compatibility of two photochemical transformations based on mechanistic differences. This one-pot process expands the limits of the decarboxylative Giese reaction beyond polarity matching.
Red-light-mediated Barton decarboxylation using catalytic zinc tetraphenylporphyrin was developed. One-pot wavelength-selective reaction within the visible light range was achieved in combination with blue-light-mediated photoredox reaction.
Metal-catalyzed organic reactions in live cell have been reported over the last decade, which also enabled imaging of the cell. These examples include removal of Alloc group, reduction of azide group ...and intermolecular cross-coupling.
Indoles are important heterocycles in pharmaceuticals and agrochemicals, and their atom‐economical synthesis is needed. Herein, we describe the synthesis of indoles using sigmatropic rearrangements. ...The N‐allylaniline was oxidized by environmentally benign hydrogen peroxide, and spontaneous 2,3‐Meisenheimer rearrangement gave N‐allyloxyaniline. Subsequent treatment with a ruthenium catalyst afforded N‐vinyloxyaniline, which underwent 3,3‐sigmatropic rearrangement to give indoles, expelling water as the only byproduct. The whole sequence is free of quantitative salt byproducts, thereby avoiding aqueous work up and cutting off the inorganic waste.
Display omitted
•Furan and propiolate equipped with chiral auxiliary afforded Diels–Alder product.•Solvent- and pendant group-dependence suggests aluminium coordination model.•Reaction between ...pyrrole and propiolate gave Friedel–Crafts-type adducts.
We report the first asymmetric Diels–Alder reaction between furan and propiolates. Propiolate, a dienophile, was equipped with an Evans’ auxiliary and a sulfonyl group to control and facilitate diastereoselective cycloaddition. Treatment with furan as a diene and aluminium Lewis acid afforded a 7-oxabicyclo2.2.1heptadiene skeleton diastereoselectively. The origin of diastereoselectivity can be explained by chelation of aluminium center to carbonyl groups and oxygen of furan. Friedel–Crafts-type products were obtained when pyrrole was used as diene.
In Vivo Gold Complex Catalysis within Live Mice Tsubokura, Kazuki; Vong, Kenward K. H.; Pradipta, Ambara R. ...
Angewandte Chemie,
March 20, 2017, Letnik:
129, Številka:
13
Journal Article
Recenzirano
Metal complex catalysis within biological systems is largely limited to cell and bacterial systems. In this work, a glycoalbumin–AuIII complex was designed and developed that enables organ‐specific, ...localized propargyl ester amidation with nearby proteins within live mice. The targeted reactivity can be imaged through the use of Cy7.5‐ and TAMRA‐linked propargyl ester based fluorescent probes. This targeting system could enable the exploitation of other metal catalysis strategies for biomedical and clinical applications.
Die erste Metall‐katalysierte Reaktion in lebenden Mäusen basiert auf der Verwendung von Glycanen. Glycoalbumin‐AuIII‐Komplexe akkumulieren in spezifischen Organen, wo sie die Amidbildung zwischen einer Propargylestersonde und einem Amin eines nahen Proteins katalysieren. Die Organselektivität wurde durch Ganzkörperfluoreszenzbildgebung und die Analyse sezierter Gewebe bestätigt.
PDF
