Activation of metal-bound η5-C5Me5groups to Diels–Alder addition of 3O2 and other dienophiles

Abstract

Pt(η⁵-C₅Me₅)(PR₃)I (PR₃ = PPh₃, PPhCy₂, PPhMe^tBu) reacts with ³O₂ to form the metal-bound endoperoxide Pt(η¹,η²-C₅Me₅O₂)(PR₃)I; analogous reactions of Pt(η⁵-C₅Me₅)(PPh₃)I with a variety of other dienophiles to form Pt(η¹,η²-C₅Me₅CH₂CHR)(PPh₃)I (R = C(O)H, CO₂Me, C(O)Et) in which the metal is anti to the incoming dienophile are indicative of direct Diels–Alder addition to the η⁵-C₅Me₅ ring.