Stereocontrolled synthesis of bicyclic ureas and sulfamides via Pd-catalyzed alkene carboamination reactions.

The synthesis of bicyclic ureas and sulfamides via palladium-catalyzed alkene carboamination reactions between aryl/alkenyl halides/triflates and alkenes bearing pendant cyclic sulfamides and ureas is described. The substrates for these reactions are generated in 3-5 steps from commercially available materials, and products are obtained in good yield with up to >20:1 diastereoselectivity. The stereochemical outcome of the sulfamide alkene addition is consistent with a mechanism involving -aminopalladation of the alkene, whereas the stereochemical outcome of the urea alkene addition is consistent with a -aminopalladation mechanism.

Enantioselective Folding of Enynes by Gold(I) Catalysts with a Remote -Chiral Element.

Chiral gold(I) catalysts have been designed based on a modified JohnPhos ligand with a distal -2,5-diarylpyrrolidine that creates a tight binding cavity. The -chiral element is close to where the C-C bond formation takes place in cyclizations of 1,6-enynes. These chiral mononuclear catalysts have been applied for the enantioselective 5--dig and 6--dig cyclization of different 1,6-enynes as well as in the first enantioselective total synthesis of three members of the carexane family of natural products.

Synthesis of Substituted γ- and δ-Lactams via Pd-Catalyzed Alkene Carboamination Reactions.

The synthesis of substituted γ- and δ-lactams via palladium-catalyzed alkene carboamination reactions between aryl halides and alkenes bearing pendant amides is described. The substrates for these reactions are generated in 1-3 steps from commercially available materials, and products are obtained in good yield with up to >20:1 diastereoselectivity. The stereochemical outcome of the alkene addition is consistent with a mechanism involving anti-aminopalladation of the alkene.

Phenotypic screening with oleaginous microalgae reveals modulators of lipid productivity.

Here we describe the first phenotypic screening with microalgae to study lipid metabolism and to discover organic small molecules as chemical triggers that increase growth and lipid production. A microplate assay has been developed for analysis of intracellular lipids using Nile Red fluorescence in order to screen a collection of diverse bioactive organic molecules (e.g.