Problems and exercisesThe Sonogashira coupling
Exercise 1
Propose a synthesis of diphenylacetylene from iodobenzene and trimethylsilylacetylene. Why is the latter used instead of acetylene?
Exercise 2
When a Sonogashira coupling is run without degassing the solvent, a substantial amount of 1,4-diphenylbuta-1,3-diyne is obtained from phenylacetylene. Explain its formation.