An efficient low-temperature route to polycyclic isoquinoline salt synthesis via C-H activation with [Cp*MCl2]2 (M = Rh, Ir).
Bi-, tri-, and tetracyclic isoquinoline salts were readily synthesized in excellent yields at room temperature from readily available starting materials after three reaction steps. Aromatic C-H activation was first promoted by sodium acetate with [Cp*MCl2]2 (M = Rh, Ir) at room temperature to form cyclometalated compounds. Dimethylacetylenedicarboxylate was then found to insert into the metal-carbon bonds of the cyclometalated compounds. Finally, the insertion compounds underwent oxidative coupling to form the desired isoquinoline salts and regenerate [Cp*MCl2]2. All of the intermediate compounds following C-H activation, alkyne insertion, and oxidative coupling were fully characterized, including the determination of X-ray structures in several cases, and the results shed light on the overall mechanism. Moreover, it was possible to synthesize the isoquinoline salts from readily available starting materials using one-pot procedures; thus, this work provides a novel, efficient method for metal-mediated synthesis of heterocycles.
Li
Ling
L
Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
Brennessel
William W
WW
Jones
William D
WD
D003080:Cold Temperature; D018360:Crystallography, X-Ray; D007495:Iridium / Q000737:chemistry*; D007546:Isoquinolines / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009942:Organometallic Compounds / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*
D007546:Isoquinolines; D009942:Organometallic Compounds; D007495:Iridium; D012238:Rhodium