Snapshot of the palladium(II)-catalyzed oxidative biaryl bond formation by X-ray analysis of the intermediate diaryl palladium(II) complex

摘要

Pd ~(II) caught in the act: The diaryl Pd ~(II) intermediate of a Pd ~(II)-catalyzed oxidative biaryl bond formation proceeding via a double C-H bond activation has been isolated and fully characterized, including an X-ray crystal structure analysis (see figure). Stabilization due to chelation by adjacent pivaloyloxy and acetyl groups has allowed the isolation of this long-sought crucial intermediate. On gentle warming, the complex is transformed into a carbazole product, and the catalytically active Pd ~(II) species is regenerated by oxidation with Cu ~(II).