Inverse‐Electron‐Demand Diels–Alder Reaction of Tropone with Graphene Supported on Cu(111)

Abstract An inverse‐electron‐demand Diels–Alder (IEDDA) reaction between graphene supported on Cu(111) and tropone catalyzed by a Lewis acid is reported. Reaction catalyzed by B(C ₆ F ₅ ) ₃ resulted in a significant change in the Raman G band and the appearance of carbonyl group in the functionalized graphene. Treating the product with a reducing agent NaBH ₄ or hydrazine led to a near complete disappearance of shoulder peaks in the Raman G band and a decrease in carbonyl intensity. On the other hand, reaction catalyzed by BPh ₃ resulted in the appearance of C─O group in the functionalized graphene. The findings support [4 + 2] and [8 + 2] cycloaddition for the B(C ₆ F ₅ ) ₃ ‐ and BPh ₃ ‐catalyzed reaction, respectively. Density functional theory (DFT) calculations revealed that favorable cycloaddition reactions with tropone can be achieved through the usage of curved graphene. The origin of the Lewis acid‐dependent selectivity inversion is predicted to be based on the requirement for Lewis acid dissociation during the course of the [8 + 2] reaction with B(C ₆ F ₅ ) ₃ dissociation requiring more energy than BPh ₃ dissociation. This study represents a new strategy in graphene chemistry that combines synergistic activation of graphene via substrate interactions and of tropone via Lewis acid coordination, as well as catalyst selection to modulate reaction pathways.