Enantioselective Synthesis of α-Quaternary Isochromanes by Oxidative Aminocatalysis and Gold Catalysis.

A novel strategy that combines oxidative aminocatalysis and gold catalysis allows the preparation of chiral α-quaternary isochromanes, a motif that is prevalent in natural products and synthetic bioactive compounds. In the first step, α-branched aldehydes and propargylic alcohols are transformed into α-quaternary ethers with excellent optical purities (>90 % ee) via oxidative umpolung with DDQ and an amino acid-derived primary amine catalyst. Subsequent gold(I)-catalyzed intramolecular hydroarylation affords the isochromane products with retention of the quaternary stereocenter.

Easy and convenient millimole-scale synthesis of new, potential biomarkers for gamma-hydroxybutyric acid (GHB) intake: Feasible for analytical laboratories.

New biomarkers indicating the abuse of drugs and alcohol are still of major interest for clinical and forensic sciences. The endogenous neurotransmitter and approved drug, gamma-hydroxybutyric acid (GHB), is often illegally used for drug-facilitated crimes by spiking GHB into alcoholic beverages. Analytical detection windows of only 6 h in blood and 12 h in urine are often too short to provide reliable proof of GHB ingestion.

An RCM-Based Total Synthesis of the Antibiotic Disciformycin B.

The total synthesis of the potent new antibiotic disciformycin B (2) is described, which shows significant activity against methicillin- and vancomycin-resistant Staphylococcus aureus (MRSA/VRSA) strains. The synthetic route is based on macrocyclization of a tetraene substrate to the 12-membered macrolactone core by ring-closing olefin metathesis (RCM). Although macrocyclization was accompanied by concomitant cyclopentene formation by an alternative RCM pathway, conditions were established to give the macrocycle as the major product.

Inbreeding load and inbreeding depression estimated from lifetime reproductive success in a small, dispersal-limited population.

The fitness consequences of inbreeding and the individual behaviors that prevent its detrimental effects can be challenging to document in wild populations. Here, we use field and molecular data from a 17-year study of banner-tailed kangaroo rats (Dipodomys spectabilis) to quantify the relationship between inbreeding, mate kinship, and lifetime reproductive success. Using a pedigree that was reconstructed using genetic and field data within a Bayesian framework (median probability of parental assignment = 0.

Group movements in response to competitors' calls indicate conflicts of interest between male and female grey-cheeked mangabeys.

Long-distance vocalizations mediate spacing patterns by allowing groups to choose whether to draw close enough to a neighbor to initiate a short-range interaction. It is unclear, however, whether the patterning of calls and the resulting movements are invariant or change in response to social and ecological variables. In this study, we compare the impact of long-distance calls on neighboring groups' movements in two populations of grey-cheeked mangabeys (Lophocebus albigena) in Uganda, which differed widely in group density and food availability.