An unprecedented utilization of 1,3-acetonedicarboxylic acid as a 1,3-bis-pro-nucleophile and a reactive acetone surrogate in enantioselective catalysis has been reported. By synergistically activating the ketodiacid by copper catalysis and an α,β-unsaturated aldehyde by amine catalysis, an efficient domino di-decarboxylative Michael/aldol/dehydration sequence takes place leading to valuable ch...

Per-O-methylated cyclodextrins containing a single 2-O-(2-acetate), 2-O-(3-propanoate) or a 6-carboxylate were investigated for glycosidase activity on p-nitrophenyl glycosides. The former two compounds displayed enzyme catalysis giving rate accelerations of 500-1000, while the latter compound gave marginal catalysis. These results show that per-O-methylated cyclodextrins direct substrate bindi...

Inexpensive copper catalysts enabled direct C-H chalcogenations at ambient temperature by means of photo-induced catalysis. The expedient copper catalysis set the stage for C-S and C-Se bond formation from readily accessible non-volatile elemental chalcogens. The photo-assisted copper catalysis manifold proved suitable for a wide range of substrates with good functional group tolerance and exhi...

Gold-catalyzed transformations allow efficient access to a wide scope of heterocyclic structures that serve as building blocks and pharmacophores in medicinal chemistry. Compared with other transition metal and Lewis acid catalysis, gold catalysis presents mechanistic divergence, excellent functional group tolerance and/or operational advantages. Emergent applications of gold catalysis have pla...

Dihydrofolate reductase from Escherichia coli (ecDHFR) serves as a model system for investigating the role of protein dynamics in enzyme catalysis. We discuss calculations predicting a network of dynamic motions that is coupled to the chemical step catalyzed by this enzyme. Kinetic studies testing these predictions are presented, and their potential use in better understanding the role of these...

Nature's enzymes are an ongoing source of inspiration for scientists. The complex processes behind their selectivity and efficiency is slowly being unraveled, and these findings have spawned many biomimetic catalysts. However, nearly all focus on the conversion of small molecular substrates. Nature itself is replete with inventive catalytic systems which modify, replicate, or decompose entire p...

The time of greatest sensitivity to radiation is during the period of organogenesis in the first twelve weeks of human foetal development. Irradiation of the adult can cause life shortening or increased incidence of leukemia. The last chapter is concerned with the basis and origin of radiation protection standards, the hazards of nuclear power plants, high altitude supersonic aerospace travel, ...

H ighlighting this issue of PNAS and the forthcoming one* is a Special Feature comprising 8 Perspectives and 44 research articles that cover aspects of asymmetric catalysis, the phenomenon whereby a chiral catalyst promotes the conversion of an achiral substrate to a chiral product with a preference for the formation of one of the mirror image isomers (enantiomers). The demand for chiral compou...

Alkylation of benzene with 1-dodecene catalyzed by metal-pillared montmorillonite (M-PILC, M = Al, Cr, Fe, Al-Fe, Fe-Cr) was successfully carried out. The formation of linear monoalkylbenzenes in 98% yield in the presence of Fe-PILC during two hours is remarkable. The 2-phenydodecane obtained with 30% concentration within the other 3-, 4-, 5-, and 6-monosubstituted products is similar to that o...