Synthetic Routes towards Multifunctional Cyclopentadienes.

Cyclopentadiene, and more importantly its functionalized derivatives, are a cornerstone of synthetic chemistry. Nowadays, they find applications in (chiral) catalysis, as ligands for organometallic complexes with potential diagnostic and therapeutic applications, and many more. This Minireview highlights the progress that has been made in the development of flexible and robust synthetic routes towards multifunctional cyclopentadienes in the last 20 years.