Copper-catalyzed carbonylative transformations of indoles with hexaketocyclohexane

With hexaketocyclohexane octahydrate as the carbon monoxide source, a novel procedure for copper-catalyzed direct double carbonylation of indoles has been established. Using alcohols as reaction partners, moderate to good yields of the desired double carbonylation products have been obtained. Wide functional group tolerance and substrate scope can be observed.