The regio- and stereospecific rhodium-catalyzed allylic alkylation of secondary allylic carbonates with cyanohydrin pronucleophiles facilitates the direct construction of acyclic α-ternary β,γ-unsaturated aryl ketones. Interestingly, this study illustrates the impact of deaggregating agents on regiocontrol and the electronic nature of the aryl component to suppress olefin isomerization. In addi...

A convergent, stereocontrolled route to either antipode of the cell adhesion inhibitor, peribysin E, has been achieved from carvone. Highlights of the synthesis include a Diels-Alder reaction to generate a cis-decalin framework, followed by semipinacol-type ring contraction to secure the stereochemistry of the C7 quaternary center. Potential mechanistic pathways for the critical ring contractio...

We have developed a novel organometallic catalysis and applied it to drug discovery. Two new catalysts were found, ruthenium hydride with a nitrogen-containing heterocyclic carbene (A) and an organopalladium catalyst supported on a sulfur-terminated semiconductor, gallium arsenide (001) (B). Both catalysts are environmentally benign, because A can yield indole derivatives with good atom economy...

Y ukiharu Sato, Toshinobu Hoshi, Tetsuji Iida, Chifuyu Ogino, B eate Nicolaus*, Ko W akabayashi, and P eter Böger* Graduate School of Agriculture, Tamagawa University, Machida-shi, Tokyo 194, Japan * Lehrstuhl für Physiologie und Biochemie der Pflanzen, Universität Konstanz, D-78434 Konstanz, Bundesrepublik Deutschland Z. Naturforsch. 49c, 49-56 (1994); received November 12,1993 Proherbicide, I...

How can you use a ruthenium isomerization catalyst twice? A ruthenium-catalyzed sequence for the formal two-carbon scission of allyl groups to carboxylic acids has been developed. The reaction includes an initial isomerization step using commercially available ruthenium catalysts followed by in situ transformation of the complex to a metal-oxo species, which is capable of catalyzing subsequent ...

Abstract The synthesis of Lipoxin B 4 analogs (LXB ) to gain access stabilized inflammation resolving compounds is an actual field research. Focusing on variation and stabilization the conjugated E,Z,E,E C6–C13 tetraene moiety natural LXB , a methylene bridge introduced between C6 C11 suppresses any Z/E isomerization C8–C9 olefin. Intending enable prospective structure variations in connection ...

Two heterogeneous catalysts, MNP@SiO2-N-Xantphos/Rh(I) and MNP@SiO2-NH-C-scorpionate/Fe(II), were prepared by reaction of chloro-functionalized MNP@SiO2 with N-Xantphos amino-functionalized iron(II)/C-allyl-scorpionate through nucleophilic substitution hydroaminomethylation reactions, respectively. All catalysts characterized using standard spectroscopic means, transmission electron microscopy ...

Catalytic isomerization of glucose to fructose by immobilized glucose isomerase in an aqueous-ethanol medium was studied. Using Michaelis-Menten equation and Haldane relationship, the main kinetic parameters were determined: Kmf, Vmf, Kmr, Vmr. By comparing the aqueous-ethanol medium with an aqueous solution, the measured values of Kmr and Kmf were increased in the aqueous-ethanol solution, whi...