Genetic and morphometric differences demonstrate fine-scale population substructure of the yellow perch Perca flavescens: need for redefined management units.

Whole-body morphometrics and 15 nuclear DNA microsatellite loci were analysed for 158 Perca flavescens collected during the spawning season from four spawning locations in central Lake Erie, two along the northern shore and two along the southern shore, to evaluate fine-scale variation (spanning 17-94 km). Results showed significant morphological and genetic differences among P. flavescens from the four locations. The magnitudes of differences were unrelated to geographic distance, demonstrating spatially heterogeneous levels of genetic divergence. These results linked morphometric and genetic variation, showing a discontinuity of scale between currently defined management units and population structure of P. flavescens in Lake Erie, and support that P. flavescens might exist as one or more metapopulations. Findings demonstrate the value of using complementary techniques for evaluating population structure.

Copper(II)-mediated oxidative coupling of 2-aminonaphthalene homologues. Competition between the straight dimerization and the formation of carbazoles.

Whereas the Cu(II)-mediated oxidative coupling of 2-aminonaphthalenes 7a and 7b results in the clean formation of 1,1'-binaphthyls 13a and 13b, respectively, their higher homologues and congeners 8-12 have been found to exhibit a different reaction pattern. Thus, 2-aminoanthracene (8) gave a approximately 1:1 mixture of the expected bianthryl derivative 15 and the carbazole 16, whereas the 9-aminophenanthrene (10), 3-phenyl-1-aminonaphthalene (11), and 2-aminochrysene (12) produced almost exclusively the corresponding carbazoles 19, 20, and 21, respectively. By contrast, the isomeric 3-aminophenanthrene (9) gave rise to the azo compound 17 as a result of the preferential oxidation on the nitrogen. The carbazoles have been shown to arise directly from the coupling reactions rather than from the primarily formed binaphthyls. Alternatively, carbazole 19 can also be prepared from 1b on reaction with hydrazine. On the other hand, treatment of 3a with hydrazine resulted in the formation of a approximately 2:7 mixture of amine 11 and arylhydrazine 22. 2,2'-Diamino-1,1'-bianthryl (15) has been resolved into enantiomers via cocrystallization with (-)-N-benzylcinchonidinium chloride and shown to have (R)-(-)-15 configuration by X-ray crystallography.

Electrochemical recognition of charged species using quaternary ammonium binaphthyl salts.

The effects of ionic analytes on the electrochemical properties of quaternary ammonium binaphthyl salts are described in this work. The stability of the binaphthyl radicals and hence the reversibility of the electrochemical response are discussed in terms of molecular structure. The ability of azacrown derivatised binaphthyl salts to act as amperometric receptors is ascribed to the strain imparted in the cyclic ammonium ring when Li+ ions complex with them. It is also shown that the redox properties of quaternary ammonium binaphthyl salts are pH dependent in aqueous solutions, but that reversible redox properties can be observed in extremely basic solutions. The effect of anions binding to the quaternary ammonium cation can be seen in the redox properties of the binaphthyl moiety and the use of a chiral binding site for enantiomeric recognition is also demonstrated.

PINDY: A novel, pinene-derived bipyridine ligand and its application in asymmetric, Copper(I)-catalyzed allylic oxidation

The title bipyridine ligand (+)-6(PINDY), prepared in five steps from (-)-beta-pinene, forms a stable complex with CuCl(2) (8) that has been characterized by X-ray crystallography to reveal an unusual geometry at Cu. Triflate 9 proved to catalyze asymmetric allylic oxidation (10 --> 11; rt, approximately 30 min, 49-75% ee).

Diastereoisomeric cationic pi-allylpalladium-(P,C)-MAP and MOP complexes and their relationship to streochemical memory effects in allylic alkylation.

The axially chiral ligands 2-(diphenylphosphanyl)-2'-methoxy-1,1'-binaphthalene (MOP; 6) and 2'-dimethylamino-2-(diphenylphosphanyl)-1,1'-binaphthalene (MAP; 7) coordinate to a cationic allylpalladium fragment in an unusual bidentate (P,C)-mode through the triarylphosphane and ipso-carbon atom (C1'). The readily prepared MAP and MOP complexes [Pd[(P,C)-(L)](n3-allyl)][OTf] (9 (L = 7) and 10 (L = 6)) have been characterised in solution (NMR), in which two diastereoisomeric rotamers are observed. The stereochemical identity of the rotamers is established by one- and two-dimensional NMR spectroscopy experiments. In both the solid state and in solution, the allyl unit is shown to coordinate in a slightly distorted n3-mode that results in a more alkene-like character at the allyl terminus trans to phosphane ligand. The opposite allyl terminus, which is trans to the ipsocarbon atom (C1'), is more strongly bound and the dominant allyl stereodynamic process involves C-C bond rotation in an n'-allyl intermediate bound through this carbon. Palladium complexes of MAP and MOP are very efficient catalysts for allylic alkylation of racemic cyclopentenyl pivalate with [NaCH(CO2Me)2] in THF. Isotopic desymmetrisation revealed that the reaction occurs with powerful stereochemical memory effects and consequently with low global ee values. The memory effect is suggested to arise through selective generation of diastereoisomeric [Pd[(P,C)-L](n3-cyclopentenyl)]+ ions (L = MAP or MOP) and subsequent capture by nucleophile before ion-pair collapse or equilibration occurs.