A tetranuclear Cu(I) double-stranded helicate was synthesized from ketimine-bridged tris(bipyridine) ligands and Cu(I) ions, and the racemate was successfully resolved by diastereomeric salt formation using an optically pure phosphate anion followed by anion exchange with NaPF(6) without racemization.

Investigation of amino acids in fossils over the past thirty years has revealed that residual amino acids may exist in fossils from throughout the Phanerozoic portion of the geologic column, that the amino acid pattern in a given fossil changes with age due to differences in stability among the twenty amino acids of which proteins are constructed, and that the ratio of right-handed to left-hand...

The unprecedented homogeneous hydrogenation of cyclic di-esters, in particular biomass-derived glycolide and lactide, to the corresponding 1,2-diols is catalyzed by Ru(II) PNN (1) and Ru(II) CNN (2) pincer complexes under mild hydrogen pressure and (in the case of 1) neutral conditions. No racemization was observed when a chiral di-ester was used.

Highly enantioselective iridium-catalyzed hydrogenation of pyrrolo[1,2-a]pyrazinium salts has been achieved, providing a direct access to chiral 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives with up to 95% ee. The key feature of the reaction is the addition of cesium carbonate, which increases the conversion and prohibits the racemization pathway of products.

The efficient total synthesis of (-)-serotobenine (1) has been achieved by constructing an optically active dihydrobenzofuran ring via a rhodium carbenoid mediated intramolecular C-H insertion reaction, which was developed by our group. Then the possibility of racemization of 1 was investigated using optically active synthetic 1.

The kinetics of enantiomerization and dynamic thermodynamic resolution (DTR) of N-Boc-2-lithiopiperidine have been measured, revealing significant differences in enthalpy and entropy for these processes and a role for the achiral ligand TMEDA; the racemization and the DTR are catalytic and first order in [TMEDA], and this has implications for asymmetric synthesis with chiral organolithiums.

The homogenous, [IrCp∗I2]2, SCRAM catalyst (1) is active in the racemization of chiral amines. NMR, kinetic and structural mechanistic studies have determined cause deactivation to occur when ammonia or methylamine are liberated by hydrolysis aminolysis intermediate imine, which tightly coordinate iridium centre block turnover. Control moisture substrate concentration can suppress deactivation,...

To obtain information on the reaction specificity of cystalysin from the spirochaete bacterium Treponema denticola, the interaction with L- and D-alanine has been investigated. Binding of both alanine enantiomers leads to the appearance of an external aldimine absorbing at 429 nm and of a band absorbing at 498 nm, indicative of a quinonoid species. Racemization and transamination reactions were...