The Chemistry and Utilization of Cyclopentadiene.

Development of a Flexible Strategy towards FR900482 and the Mitomycins

“…The reactivity of the surface species towards oxygen strongly supports this conclusion due to the easy oxidation of the ligand under an atmosphere of oxygen. As shown in http://www.wiley-vch.de/contents/jc_2111/2007/f700505_s.pdf, the surface species can be easily oxidized by oxygen at 323 K. This behavior is very similar to that of cyclopentadiene, whereas dicyclopentadiene is very stable towards oxygen 42. The reactivity of the organic species towards CO is also powerful evidence for the above deduction.…”

“…Cyclopentadiene can spontaneously dimerize to dicyclopentadiene in a Diels–Alder reaction even at room temperature, and the rate of this dimerization increases with temperature. The dimerization of cyclopentadiene is a thermodynamically reversible reaction, therefore if the temperature is raised to about the boiling point of dicyclopentadiene (443 K), the reaction is reversed and the dimer is reconverted into the monomer 42. The grafting reaction in this study was carried out at 423 K, which is close to the boiling point of dicyclopentadiene, and was followed by treatment under dynamic vacuum at 423 K. It is therefore clear that the amount of dicyclopentadiene remaining on the surface of the Y zeolite should be very low since the majority will have cracked to form cycloalkanes, which are detected by GC‐MS, or have reconverted into the monomer.…”

Synthetic Routes towards Multifunctional Cyclopentadienes

“…Simple cyclopentadiene is obtained by cracking dicyclopentadiene, a byproduct in steam cracking of other organic compounds, in a retro Diels–Alder reaction . Fabris and co‐workers used this as the starting point for their strategy towards simple yet attractive 1,2‐substituted Cps.…”

“…Simple cyclopentadienei so btained by cracking dicyclopentadiene, ab yproduct in steam cracking of other organic compounds, in ar etro Diels-Alder reaction. [57] Fabris and co-workers used this as the startingp oint for their strategy towards simple yet attractive 1,2-substituted Cps. Commercially available norbornadiene was derivatized with the desired functional groups andr eacted with 1,2,4,5-tetrazine-3,6-dicarboxylate through cycloaddition.…”

Methods for the Synthesis of Functionalized Pentacarboxycyclopentadienes

“…1,2 This remarkable acidity can be greatly enhanced by the incorporation of electron-withdrawing substitutents at each of the five carbons of the conjugated system. Indeed, the pentacarbomethoxy derivative has been reported to be as acidic as HCl (Figure 1a), 3 while the pentanitrile compound has a level of acidity on par with perchloric acid.…”