Cycloaddition is a fundamental transformation, featuring the assembly of complex cyclic molecules with multiple stereocenters. We report here silver-catalyzed [3+2]-cycloaddition 2,3-disubstituted cyclobutenones an array azomethine ylide...

A series of ruthenium olefin metathesis catalysts of the general structure (H(2)IMes)(PR(3))(Cl)(2)Ru=CHPh (H(2)IMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) have been prepared; these complexes are readily accessible in two steps from commercially available (H(2)IMes)(PCy(3))(Cl)(2)Ru=CHPh. Their phosphine dissociation rate constants (k(1)), relative rates of phosphine reassociation, and ...

A variety of phosphine oxides and sulfides can be efficiently converted directly to the corresponding phosphine boranes using oxalyl chloride followed by sodium borohydride. Optically active P-stereogenic phosphine oxides can be converted stereospecifically to phosphine boranes with inversion of configuration by treatment with Meerwein's salt followed by sodium borohydride.

The total synthesis of the endogenous inflammation resolving eicosanoid resolvin D2 (1) is described. The key steps involved a Wittig reaction between aldehyde 5 and the ylide derived from phosphonium salt 6 to give enyne 17 and condensation of the same ylide with aldehyde 7 to afford enyne 11. Desilylation of 11 followed by hydrozirconation and iodination gave the vinyl iodide 4 and Sonogashir...

Tandem carbenoid generation, ylide formation and [2,3]-rearrangement is a powerful method for the construction of bicyclic and linearly fused tricyclic systems containing a seven-membered ring.

An asymmetric sulfur ylide reaction was employed to prepare an epoxide intermediate in a convergent manner. This epoxide was efficiently transformed into D-erythro-sphingosine.

A highly diastereoselective tandem ring-enlargement and aldol condensation process involving multicomponent reactions of ethereal tricyclooxonium ylide intermediate with alcohols, mono- or dialdehydes in the presence of titanium(iv) isopropoxide is described to furnish alkoxyoctahydro-1,4-benzodioxocin-6(5H)-one ring systems.

In the mol-ecule of the title compound, (2-thienylcarbon-yl)(triphenyl-phospho-nio)methanide, C(24)H(19)OPS, the geometry around the P atom is nearly tetra-hedral and the O-C-C-P torsion angle is 2.80 (3)°. The thio-phene ring is twisted through an angle of 4.33 (4)° with respect to the plane of the carbonyl group. Inter- and intra-molecular hydrogen bonds and C-H⋯π inter-actions are present in...

The aim of this study is to identify the biochemical mechanism of phosphine toxicity and resistance, using Caenorhabditis elegans as a model organism. To date, the precise mode of phosphine action is unclear. In this report, we demonstrate the following dose-dependent actions of phosphine, in vitro: (1) reduction of ferric iron (Fe3+) to ferrous iron (Fe2+), (2) release of iron from horse ferri...

Density functional theory calculations were applied to study four previously published metal-catalyzed [2,3]-rearrangements from onium ylide intermediates, in pursuit of generalizations about when,...