Cp*Ir-Catalyzed Acceptorless Dehydrogenation of Carbon-Carbon Single Bonds

Tentainethylcyclopentadienyl (Cp*) iridium (III) chloride catalyzed acceptorless dehydrogenation of alpha-tetralone is, reported. Cp* iridium chloride showed higher activity in comparison to other Cp* iridium complexes having bromide, iodide, or,hydride or complexes without a Cp ring. The desired product, naphthol, was obtained in up to 71% yield from alpha-tetralone. The dehydrogenation IT Cp* iridium catalyst could be applied to not only alpha-tetralone but also dihydrocoumarin, dihydroquinolinone, dimethylcyclohexanone, dihydrobenzofuran and 1-isochromanone, although the conversion stayed moderate. The catalytic turnover was, not limited by the increased concentration of the product but by catalyst decomposition.