Base-catalysed 18F-labelling of trifluoromethyl ketones. Application to the synthesis of 18F-labelled neutrophil elastase inhibitors.

A new method for the fluorine-18 labelling of trifluoromethyl ketones has been developed. This method is based on the conversion of a-COCF3 functional group to a difluoro enol silyl ether followed by halogenation and fluorine-18 labelling. The utility of this new method was demonstrated by the synthesis of fluorine-18 labelled neutrophil elastase inhibitors, which are potentially useful for detection of inflammatory disorders.

Trifluoromethylthiolation, Trifluoromethylation, and Arylation Reactions of Difluoro Enol Silyl Ethers.

This study reports a new application area of difluoro enol silyl ethers, which can be easily obtained from trifluoromethyl ketones. The main focus has been directed to the electrophilic fluoroalkylation and arylation methods. The trifluoromethylthiolation of difluoro enol silyl ethers can be used for the construction of a novel trifluoromethylthio-α,α-difluoroketone (-COCF2SCF3) functionality. The -CF2SCF3 moiety has interesting properties due to the electron-withdrawing, albeit lipophilic, character of the SCF3 group, which can be combined with the high electrophilicity of the difluoroketone motif. The methodology could also be extended to difluoro homologation of the trifluoromethyl ketones using the Togni reagent. In addition, we presented a method for transition-metal-free arylation of difluoro enol silyl ethers based on hypervalent iodines.

Rhodium-mediated 18F-oxyfluorination of diazoketones using a fluorine-18-containing hypervalent iodine reagent.

Geminal 18F-oxyfluorination of diazoketones was performed in the presence of rhodium mediators. The reactions were performed using a hypervalent iodine-based [18F]fluoro-benziodoxole reagent. By this methodology various α-[18F]fluoro ethers were obtained in high radiochemical yield (up to 98%) and molar activity (216 GBq µmol-1).

Iron Catalysis for Room-Temperature Aerobic Oxidation of Alcohols to Carboxylic Acids.

Oxidation from alcohols to carboxylic acids, a class of essential chemicals in daily life, academic laboratories, and industry, is a fundamental reaction, usually using at least a stoichiometric amount of an expensive and toxic oxidant. Here, an efficient and practical sustainable oxidation technology of alcohols to carboxylic acids using pure O2 or even O2 in air as the oxidant has been developed: utilizing a catalytic amount each of Fe(NO3)3·9H2O/TEMPO/MCl, a series of carboxylic acids were obtained from alcohols (also aldehydes) in high yields at room temperature. A 55 g-scale reaction was demonstrated using air. As a synthetic application, the first total synthesis of a naturally occurring allene, i.e., phlomic acid, was accomplished.

Redox stimuli-responsive hollow mesoporous silica nanocarriers for targeted drug delivery in cancer therapy.

In order to specifically deliver drugs into cancer cells with targeted recognition and controlled release, biocompatible hollow mesoporous silica nanocarriers with tumor-targeting and glutathione-responsive release dual properties were developed. These multifunctional nanocarriers were fabricated by anchoring transferrin on the surface of hollow mesoporous silica nanoparticles through disulfide bond conjugation, which could be cleaved in the presence of glutathione. In this case, transferrin acted as the gatekeeper to control the drug release, and as a tumor-targeting agent to improve drug accumulation at the tumor site simultaneously. The detailed investigations indicate that the anticancer drug (doxorubicin) release from the nanocarriers was strongly dependent on the concentration of glutathione. The capacity of the nanocarriers to selectively deliver doxorubicin to the tumor cells was demonstrated in vitro and in vivo. The doxorubicin-loaded nanocarriers showed enhanced inhibition of tumor growth and minimal side-effects in vivo compared to free doxorubicin. These redox stimuli-responsive nanocarriers that achieved a combination of tumor targeting and controlled drug release provide a promising platform for efficient cancer therapies.

General CuBr2-catalyzed highly enantioselective approach for optically active allenols from terminal alkynols.

Here, we show a CuBr2-catalyzed approach for a highly enantioselective synthesis (93-99% ee) of allenols from aldehydes and terminal alkynols with the absolute configuration being controlled by applying readily available (R)- or (S)-α,α-diphenylprolinol.

Mussel-inspired gold hollow superparticles for photothermal therapy.

Gold hollow superparticles are prepared taking advantage of the dopamine chemistry. The plasmon coupling of the gold nanoparticles makes the superparticles an effective photothermal conversion agent in the photothermal therapy of cancer. Moreover, the mussel-inspired assembly approach could be extremely useful for the transfer of nanomaterial science to realistic technologies.