Nematode parasites of humans, livestock and crops dramatically impact human health and welfare. Alarmingly, parasitic nematodes of animals have rapidly evolved resistance to anthelmintic drugs, and traditional nematicides that protect crops are facing increasing restrictions because of poor phylogenetic selectivity. Here, we exploit multiple motor outputs of the model nematode C.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2021
Enantioenriched spiro-oxiranes bearing three contiguous stereocenters were synthesized using a rhodium-catalyzed asymmetric addition/aldol/spirocyclization sequence. Starting from a linear substrate, the cascade enabled the formation of a spirocyclic framework in a single step. sp - and sp-hybridized carbon nucleophiles were found to be competent initiators for this cascade, giving arylated or alkynylated products, respectively.
View Article and Find Full Text PDFA rhodium-catalyzed conjugate alkynylation/aldol cyclization cascade was developed. Densely functionalized cyclic α-propargyl-β-hydroxyketones were synthesized with simultaneous formation of a C(sp)-C(sp) bond, a C(sp)-C(sp) bond, as well as three new contiguous stereocenters. The transformation was achieved with excellent enantio- and diastereoselectivities using BINAP as the ligand.
View Article and Find Full Text PDFThe α-methyl ester sulfonate, MES, anionic surfactants are a potentially important class of sustainable surfactants for a wide range of applications. The eutectic-like Kraft point minimum in the C and C-MES mixtures is an important feature of that potential. Understanding their individual adsorption properties and the surface mixing of the eutectic mixtures are key to their wider exploitation.
View Article and Find Full Text PDFHerein we describe a rhodium-catalyzed enantioselective isomerization of meso-oxabicyclic alkenes to 1,2-naphthalene oxides. These potentially useful building blocks can be accessed in moderate to excellent yields with impressive enantioselectivities. Additionally, experimental findings supported by preliminary computations suggest that ring-opening reactions of bridgehead disubstituted oxabicyclic alkenes proceed through the intermediacy of these epoxides and may point to a kinetically and thermodynamically favored reductive elimination as the origin for the observed enantioselectivities.
View Article and Find Full Text PDFA rhodium-catalyzed cyclization of 1-(trifluoromethyl)-4-alkyn-1-ones with arylboronic acids is described to yield a novel class of small rings: (trifluoromethyl)cyclobutanols bearing an exocyclic double bond. The use of a rhodium/chiral diene complex allowed the reaction to proceed under mild conditions, often with high enantioselectivity. An X-ray crystal structure was obtained confirming the formation of the four-membered ring products.
View Article and Find Full Text PDFThe epimerization of amino acid residues increases with age in living organisms. In the present study, the structural consequences and thermodynamic functions of the epimerization of thymopentin (TP-5), the active site of the thymic hormone thymopoietin, were studied using molecular dynamics and density functional theory methods. The results show that free radical-initiated D-amino acid formation is energetically favoured (-130 kJmol(-1)) for each residue and induces significant changes to the peptide structure.
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