Ene-Yne Metathesis

Ene-yne metathesis is the carbon-carbon bond coupling that occurs between an alkene and an alkyne with pi bond reorganization. By far the most common use of ene-yne metathesis is the ring-closing enyne metathesis (RCEYM). When the reaction occurs between two separate molecules in an intermolecular reaction, it is known as a cross ene-yne metathesis. For the reaction to occur, the alkene must be reactive with the Grubbs carbene being used. Enyne metathesis is valuable as a part of cascading metathesis reactions that form two or more rings. The cascade or tandem processes are discussed in this chapter. The chapter describes sequential metathesis reactions that form a single ring. It also describes cascade ring-closing applications that form two rings or more. Last, the chapter discusses tandem metathesis reactions that result in ring rearrangement.