The discovery of highly active catalysts and the success of ionic liquid immobilized systems have accelerated attention to a new class of cationic metathesis catalysts. We herein report the facile syntheses of cationic ruthenium catalysts bearing bulky phosphine ligands. Simple ligand exchange using silver(i) salts of non-coordinating or weakly coordinating anions provided either PPh3 or chelat...

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 ...

An analog of mycothiazole and pseudotrienic acid B were synthesized efficiently by using ring-closing metathesis or cross-metathesis as key reactions.

A series of cyclometalated Z-selective ruthenium olefin metathesis catalysts with alterations to the N-heterocyclic carbene (NHC) ligand were prepared. X-Ray crystal structures of several new catalysts were obtained, elucidating the structural features of this class of cyclometalated complexes. The metathesis activity of each stable complex was evaluated, and one catalyst, bearing geminal dimet...

Various substituted Dispiro [pyrrolo-piperazino-oxindole] have been synthesized by utilizing a simple and efficient two-step synthetic protocol Grubbs metathesis in dichloromethane at 40°C. The structures relative stereochemistry of the cycloadduct were confirmed single-crystal X-ray diffraction, 1H 13C NMR spectroscopy, mass spectrometry.
 
 Keywords: Hexahydro-diazecane-dione, Metat...

Catalytic asymmetric ring-opening metathesis (AROM) provides an efficient method for the synthesis of a variety of optically enriched small organic molecules that cannot be easily prepared by alternative methods. The development of Mo-catalyzed AROM transformations that occur in tandem with ring-closing metathesis are described. The utility of the Mo-catalyzed AROM/ring-closing metathesis is de...

Recombinant peptide synthesis allows for large-scale production of peptides with therapeutic potential. However, access to dicarba peptidomimetics via sidechain-deprotected sequences becomes challenging exposed Lewis basicity presented by amine and sulfur-containing residues. Presented here is a combination strategies which can be used deactivate coordinative residues achieve high-yielding Ru-c...

The Z-selective cross metathesis of allylic-substituted olefins is explored with recently developed ruthenium-based metathesis catalysts. The reaction proceeds with excellent stereoselectivity for the Zisomer (typically >95%) and yields of up to 88% for a variety of allylic substituents. This includes the first synthesis of Z-a,b-unsaturated acetals by cross metathesis and their elaboration to ...