Tandem Ring-closing Metathesis Reaction Research Articles

ChemInform Abstract: Construction of the Basic Skeleton of Ophiobolin A (I) and Variecolin (II)

Abstractinvolving a tandem ring closing metathesis reaction of dienynes as key step

Generation of Anti-trypanosomal Agents through Concise Synthesis and Structural Diversification of Sesquiterpene Analogues

To access high-quality small-molecule libraries to screen lead candidates for neglected diseases exemplified by human African trypanosomiasis, we sought to develop a synthetic process that would produce collections of cyclic scaffolds relevant to an assortment of natural products exhibiting desirable biological activities. By extracting the common structural features among several sesquiterpenes, including artemisinin, anthecularin, and transtaganolides, we designed six types of scaffolds with systematic structural variations consisting of three types of stereochemical relationships on the sp(3) ring-junctions and two distinct arrays of tricyclic frameworks. A modular and stereodivergent assembly of dienynes exploiting a versatile manifold produced a series of cyclization precursors. Divergent cyclizations of the dienynes employing tandem ring-closing metathesis reactions overrode variant reactivities of the cyclization precursors, leading to the six canonical sets of the tricyclic scaffolds incorporating a diene group. Screenings of trypanosomal activities of the canonical sets, as well as regio- and stereoisomers of the tricyclic dienes, allowed generation of several anti-trypanosomal agents defining the three-dimensional shape of the pharmacophore. The candidate tricyclic dienes were selected by primary screenings and further subjected to installation of a peroxide bridge, which generated artemisinin analogues that exhibited potent in vitro anti-trypanosomal activities comparable or even superior to those of artemisinin and the approved drugs, suramin and eflornithine.

Synthesis of Small and Large Fused Bicyclic Compounds by Tandem Dienyne Ring-Closing Metathesis

A tandem ring-closing metathesis reaction using ruthenium catalyst was carried out to synthesize various fused bicyclic compounds containing both small and large rings. Fast ring-closure of the small ring and slow ring-closure of the large ring resulted in the formation of only one isomer. Further manipulation such as the Diels-Alder reaction was carried out to prepare a complex molecule containing multiple rings of different sizes.

Synthesis of the Tricyclic Core of Colchicine via a Dienyne Tandem Ring-Closing Metathesis Reaction

The synthesis of the tricyclic framework of colchicine has been achieved using a tandem ring-closing metathesis reaction of dienynes as the key step. In this process, both seven-membered rings B and C were formed in one step. Oxidation of tertiary allylic alcohol derived from the tandem metathesis product furnished an intermediate in the total synthesis of colchicine.

An efficient construction of bicyclic systems containing a seven-membered ring by tandem ring-closing metathesis reactions of dienynes

Various (5–7) and (6–7) bicyclic dienes bearing quaternary methyl group and ester functionality have been synthesized from acyclic dienynes by tandem ring-closing metathesis (RCM) reaction. Epoxidation of these conjugated dienes led to bicyclic vinyl oxiranes which undergo acid-catalyzed addition of alcohols to afford highly oxygenated compounds.

Investigation of Diastereoselective Tandem Ring Closing Metathesis Reactions Toward the Synthesis of Functionalised Spirocyclic Piperidines

The stereoselective synthesis of a spiropiperidine through a diastereoselective tandem ring closing metathesis (RCM) reaction is reported. The efficient relay of stereochemistry from a pentyl chain to the newly formed spirocentre three carbon atoms away was found to be particularly dependant on the nature of the Ru-catalyst employed - 1st generation Grubbs catalyst was found to be significantly more selective than the more active 2nd generation carbene complexes.

Synthesis of a Highly Functionalized Tricyclic Ring System Related to Guanacastepene via a Tandem Ring‐Closing Metathesis Reaction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of a highly functionalized tricyclic ring system related to guanacastepene via a tandem ring-closing metathesis reaction

A new approach to a highly functionalized 5,7,6-tricyclic core structure of guanacastepene has been developed using the tandem ring-closing metathesis reaction of dienynes as the key step.

Tandem ring-closing metathesis reaction with a ruthenium catalyst containing a N-heterocyclic ligand

The highly active catalyst 2 was used in tandem RCM to make molecules with various ring systems containing α,β-unsaturated carbonyl compounds.

ChemInform Abstract: The Synthesis of Angularly Fused Tricyclic Compounds via Tandem Ring Closing Metathesis Reactions.

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The synthesis of angularly fused tricyclic compounds via tandem ring closing metathesis reactions

A novel and highly efficient approach to angularly fused tricycles has been developed through the employment of selective tandem ring closing metathesis reactions.

Spirocycle assembly through selective tandem ring closing metathesis reactions

A range of functionalised spirocyclic systems have been prepared under mild and neutral conditions by tandem selective ring closing olefin metathesis reactions. Additionally, a marked preference for 5-membered ring closure over 7-membered ring closure was observed which appears to be a result of a kinetically favoured cyclisation process.