A ruthenium complex bearing an "anti-Bredt" N-heterocyclic carbene was synthesized, characterized and evaluated as a catalyst for olefin metathesis. Good conversions were observed at room temperature for the formation of di- and tri-substituted olefins by ring-closing metathesis. It also allowed for the ring-opening metathesis polymerization of cyclooctadiene, as well as for the cross-metathesi...

BACKGROUND α,ω-Difunctional substrates are useful intermediates for polymer synthesis. An attractive, sustainable and selective (but as yet unused) method in the chemical industry is the oleochemical cross-metathesis with preferably symmetric functionalised substrates. The current study explores the cross-metathesis of methyl oleate (1) with cis-2-butene-1,4-diyl diacetate (2) starting from ren...

Olefin metathesis has emerged as a promising strategy for modulating the stability and activity of biologically relevant compounds; however, the ability to control olefin geometry in the product remains a challenge. Recent advances in the design of cyclometalated ruthenium catalysts has led to new strategies for achieving such control with high fidelity and Z selectivity, but the scope and limi...

Fully substituted olefin generation via metathesis is presented. Catalyst development, optimization of reaction conditions and substrate screening are included. In addition, asymmetric alkene metathesis, the cross metathesis reaction for this transformation and its application in natural products will be discussed.

Recent decades have seen a burgeoning of interest in olefin metathesis, as witnessed by a rapidly growing number of elegant applications. Using this tool, chemists can now efficiently synthesize an impressive range of molecules that only a decade ago required significantly longer and tedious routes.[1] Several types of olefin metathesis have been identified so far, among them ring-closing metat...

2-Silicon-substituted 1,3-dienes containing non transferrable groups known to promote transmetallation were prepared by Grignard chemistry and enyne metathesis. These dienes participated in one pot metathesis/Diels-Alder reactions in regio- and diastereoselective fashions. Electron-rich alkenes showed the fastest rates in metathesis reactions, and ethylene, a commonly used metathesis promoter s...

Ring-rearrangement metathesis (RRM) involves multiple metathesis processes such as ring-opening metathesis (ROM)/ring-closing metathesis (RCM) in a one-pot operation to generate complex targets. RRM delivers complex frameworks that are difficult to assemble by conventional methods. The noteworthy point about this type of protocol is multi-bond formation and it is an atom economic process. In th...

Alkyne metathesis is increasingly explored as a reliable method to close macrocyclic rings, but there are no prior examples of an alkyne-metathesis-based homodimerization approach to natural products. In this approach to the cytotoxic C2-symmetric marine-derived bis(lactone) disorazole C1, a highly convergent, modular strategy is employed featuring cyclization through an ambitious one-pot alkyn...

An approach to the synthesis of pseudo-oligosaccharides based on the cross-metathesis reaction between distinct sugar-olefins, followed by intramolecular cyclization of the obtained heterodimer, is presented. In particular, the relative efficiency of two alternative approaches, the straightforward cross-metathesis reaction and the two-step procedure (self-metathesis followed by cross-metathesis...

The asymmetric total synthesis of pyranicin (1) is reported. The butenolide ring was constructed via an asymmetric alkylation/ring-closing metathesis strategy. The three stereocenters in the left-hand tetrahydropyran ring were installed by sequential chiral auxiliary-mediated aldol reactions. Closure of the tetrahydropyran and fusion of the alkyl backbone were affected via a sequential ring-clo...