The observed single-handedness of biological amino acids and sugars has long been attributed to autocatalysis. However, the stability of homochiral states in deterministic autocatalytic systems relies on cross inhibition of the two chiral states, an unlikely scenario for early life self-replicators. Here, we present a theory for a stochastic individual-level model of autocatalysis due to early ...

Coupling of racemic N-protected amino acids with amino components by means of 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) in the presence of chiral tertiary amines such as strychnine, brucine, and sparteine proceeds enantioselectively, affording appropriate amides or dipeptides in 69-85% yield. The configuration of the preferred enantiomer and enantiomeric enrichment depend on the structures o...

Chiral tetrathiafulvalenes, (R) or (S), or racemic, (R,S), are obtained from a phosphite-mediated cross coupling reaction of a 1,3-dithiole-2-thione derivative bearing one binaphthol moiety, and are transformed into binaphthol-based tetrathiafulvalene ortho-diamides. The X-ray crystal structures of five intermediate chiral 1,3-dithiole-2-one and 1,3-dithiole-2-thione derivatives reveal the form...

In order to understand and rationally construct homochiral self-assembled structures from racemic molecules, two novel crystalline metal-organic frameworks with chiral cavities were developed. The homochirality of the layers in both MOFs was achieved by forming strong coordinate bonds between the C3-symmetric cyclotriveratrylene and Zn4O(CO2)6 cluster. By changing weak π-π interactions between ...

Advances in nanotechnology have seen the development of several microbiocidal nanoparticles displaying activity against biofilms. These applications benefit from one or more combinations of the nanoparticle properties. Nanoparticles may indeed concentrate drugs on their surface resulting in polyvalent effects and improved efficacy to fight against bacteria. Nanodiamonds (NDs) are among the most...

Homochirality of amino acids, sugars, proteins, and DNA is one of the biochemical hallmarks of life on Earth. Its origins have been debated for decades. Given that minerals such as quartz were probably the first enantiomerically pure materials on Earth, it has been suggested that such materials served as chiral substrates for enantiospecific surface chemistry. Enantiospecific adsorption on the ...

The enantioselective silylation of racemic alcohols, where one enantiomer reacts faster than the other, is an alternative approach to established enzymatic and non-enzymatic acylation techniques. The existing art is either limited to structurally biased alcohols or requires elaborate catalysts. Simple substrates, such as benzylic and allylic alcohols, with no coordinating functionality in the p...

Asymmetric 1,3-dipolar cycloadditions between 1,2-diaza-1,3-dienes and chiral non-racemic nitrones to give 3-substituted-5-diazenyl isoxazolidines were studied both experimentally and theoretically. Whereas cyclic nitrones provide complete selectivity for the cycloaddition reaction (only one isomer is obtained), acyclic nitrones derived from D-glyceraldehyde and D-galactose lead to 1 : 1 mixtur...

The HPLC enantiomeric separation of the racemic cularinoid alkaloids N-p-methoxy-1,alpha-dihydroaristoyagonine (1) and 4',5'-demethoxy-1,alpha-dihydroaristoyagonine (2) was accomplished using five chiral stationary phases (CSPs), some of them polysaccharide-derived ones. The molecular size and conjugative effect strongly affect the different enantioselectivity of the compounds 1 and 2 on the va...

BACKGROUND The Food and Drug Administration currently is assessing the public health impact of menthol cigarettes. Whether menthol cigarettes pose increased barriers to quitting is a critical issue because previous declines in smoking prevalence have stalled. PURPOSE To explore whether menthol cigarette smokers are less likely to quit than non-menthol smokers at the population level and wheth...