Question

Identify X, an intermediate that was converted to eletriptan (trade name Relpax), a drug used to treat migraines.

Short answer

The reaction between an alkene and an alkyl halide group in the presence of a base and a catalyst (palladium) is known as the Heck reaction. In this reaction, an alkene is formed.

Step-by-step solution

Heck reaction

The reaction between an alkene and an alkyl halide group in the presence of a base and a catalyst (palladium) is known as the Heck reaction. In this reaction, an alkene is formed.

Mechanism of Heck reaction  

• In the first step, the divalent palladium catalyst reacts with the alkyl halide (RX) to form an organo-palladium compound.

• In the second step, the (R) group and palladium (Pd) from the organopalladium compound add to the C=C such that Pd bonds with the more substituted carbon.
• In the third step, the elimination of hydrogen and palladium takes place. Then, by reductive elimination, the initial palladium catalyst is regenerated.

Products of the given reaction

Compound X is shown here under.