Metathesis Cascade Research Articles

Enantioselective Total Synthesis of (−)‐Acylfulvene and (−)‐Irofulven

We report our full account of the enantioselective total synthesis of (-)-acylfulvene (1) and (-)-irofulven (2), which features metathesis reactions for the rapid assembly of the molecular framework of these antitumor agents. We discuss (1) the application of an Evans Cu-catalyzed aldol addition reaction using a strained cyclopropyl ketenethioacetal, (2) an efficient enyne ring-closing metathesis cascade reaction in a challenging setting, (3) the reagent IPNBSH for a late-stage reductive allylic transposition reaction, and (4) the final RCM/dehydrogenation sequence for the formation of (-)-acylfulvene (1) and (-)-irofulven (2).

Diene, Enyne, and Diyne Metathesis in Natural Product Synthesis

AbstractFor Abstract see ChemInform Abstract in Full Text.

Ene–yne metathesis of polyunsaturated norbornene derivatives

Norbornene derivatives bearing endo-substituents in the 5- and 6-positions were studied as substrates for ene–yne metathesis cascades. Substrates which contained an internal alkyne and a terminal alkene or alkyne in each sidechain were found to undergo a metathesis cascade leading to pentacyclic bis-dienes and bis-trienes. Attempts to extend the chemistry further to sidechains containing two internal alkynes or two internal alkynes and a terminal alkene were not successful with the first generation Grubbs' catalyst. However, the substrate containing two internal alkynes did react with the second generation Grubbs' catalyst to give a tetra-diene containing product.

ChemInform Abstract: Ruthenium‐Catalyzed Conversion of Triynes to Benzene Derivatives — A Novel Metathesis Cascade.

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Ruthenium-catalysed conversion of triynes to benzene derivatives—a novel metathesis cascade

In a novel application of [PhCH2Ru(PCy3)2Cl2] 1, triynes are isomerised to benzene derivatives; a cascade of four metathesis reactions is proposed as a mechanistic explanation.