An enantioselective synthesis of (+)-corynomycolic acid, and its elaboration to esters of trehalose, glucose and glycerol, is described. Trehalose dicorynomycolate and trehalose monocorynomycolate activate human and mouse Mincle as effectively as trehalose dicorynomycolate (cord factor). Glucose monomycolate is revealed to be a potent activator of both mouse and human Mincle. Glycerol monocorynomycolate signals through human Mincle, with the activity predominantly residing in the 2'S-isomer.

Lab-on-a-chip and miniaturized systems have gained significant popularity motivated by marked differences in material performance at the micro-to-nano-scale realm. However, to fully exploit micro-to-nano-scale chemistry, solvent volatility and lack of reproducibility need to be overcome. Here, we combine the non-volatile and versatile nature of ionic liquids with microcontact printing in an attempt to establish a facile protocol for high throughput fabrication of open microreactors and microfluidics. The micropatterned ionic liquid droplets have been demonstrated as electrochemical cells and reactors for microfabrication of metals and charge transfer complexes, substrates for immobilization of proteins and as membrane-free high-performance amperometric gas sensor arrays. The results suggest that miniaturized ionic liquid systems can be used to solve the problems of solvent volatility and slow mass transport in viscous ionic liquids in lab-on-a-chip devices, thus providing a versatile platform for a diverse number of applications.

The oxygen reduction reaction plays a vital role in several processes and applications including energy and gas sensors that have been widely studied in aqueous and organic solvents. Although ionic liquids (ILs) have been known for a century, they gained substantial attention of researchers only a few decades ago as solvents for many applications like sensors, synthesis, catalysis, electrodeposition and energy applications. Use of ILs as an electrolyte for fuel cells, Li–O2 batteries and electrochemical gas sensors can resolve the issues related to instability/decompsotion, flamability and evaporation of electrolytes. Understanding the fundamentals of the ORR in ILs is essential for the development of these devices. Both the electrode materials and structure of ILs have significant effects on ORR. In addition, solubility and diffusion of O2 play an important part. This review focuses on recent advancements of ORR in ILs for energy (Li−O2 batteries and fuel cells) and electrochemical gas sensor applications. A brief introduction of ILs, followed by ORR mechanism in both aprotic and protic ILs are presented. In addition, the influence of electrode materials and ILs structure on ORR and solubility and mass transport of O2 in vaious IL-based electrolytes are also presented. Finally, some future directions with special emphasis on Li–O2 batteries, proton exchange membrane fuel cells (PEMFCs) and gas sensors are suggested.

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The synthesis of each of the heptamethyl ethers of the mulberry Diels-Alder adducts chalcomoracin (1) and mulberrofuran J (2) is described. The key steps in each approach involved a biomimetic intermolecular [4+2]-cycloaddition between a dehydroprenylphenol diene derived from an isoprenoid-substituted phenolic compound and an alpha,beta-unsaturated alkene of a chalcone as the dienophile. Critical to the success of the Diels-Alder reaction was the presence of the free phenol in the 2'-hydroxychalcone.

Electrochemical reduction of Cu(II) and electrodeposition of copper were studied in two room temperature protic ionic liquids (PILs), ethylammonium nitrate and triethylammonium methylsulfonate by using voltammetric techniques. The results provided evidence that slow disproportionation of Cu(I) occurred in the PILs. Images obtained by scanning electron microscopy revealed that electrodeposition of Cu nanoparticles and crystalline thin films onto glassy carbon and indium tin oxide electrodes occurred via two distinctly different, potential-dependent pathways: (i) disproportionation of Cu(I), at mild potentials in the range of 0.48 to 0.03 V vs. Fc 0/+ , and (ii) electroreduction of Cu(I), at potentials lower than 0.03 V vs. Fc 0/+ . The electrodeposition mechanisms were examined by using chronoamperometry and were found to be governed by instantaneous nucleation and diffusion-controlled growth kinetics.

Chiral epoxides-such as ethyl and methyl (S)-3-(oxiran-2-yl)propanoates ((S)-1a/1b)-are valuable precursors in many chemical syntheses. Until recently, these compounds were synthesized from glutamic acid in four steps (deamination, reduction, tosylation and epoxide formation) in low to moderate overall yield (20%-50%). Moreover, this procedure requires some harmful reagents such as sodium nitrite ((eco)toxic) and borane (carcinogen). Herein, starting from levoglucosenone (LGO), a biobased chiral compound obtained through the flash pyrolysis of acidified cellulose, we propose a safer and more sustainable chemo-enzymatic synthetic pathway involving lipase-mediated Baeyer-Villiger oxidation, palladium-catalyzed hydrogenation, tosylation and treatment with sodium ethoxide/methoxide as key steps. This route afforded ethyl and methyl (S)-3-(oxiran-2-yl)propanoates in 57% overall yield, respectively. To demonstrate the potentiality of this new synthetic pathway from LGO, the synthesis of high value-added (S)-dairy lactone was undertaken from these epoxides and provided the target in 37% overall yield from LGO.

The methyl ether derivatives 2, 4 and 6 of the mulberry Diels-Alder adducts chalcomoracin (1) and mulberrofuran C (3) and kuwanon J (5) respectively have been synthesized by a thermal [4 + 2]-cycloaddition reaction between a chalcone and dehydroprenyl diene. A H-bonded ortho OH substituent on the chalcone was found to be essential for Diels-Alder reactivity. Density functional theory calculations show that the OH group lowers the barrier for the Diels-Alder reaction by 2-3 kcal mol(-1) compared with OMe. The acceleration by the OH group is traced to two transition-state effects: a stronger diene-chalcone interaction and better planarity of the aryl-diene unit.