Gold-catalyzed deacylative cycloisomerization reactions of 3-acylindole/ynes: a new approach for carbazole synthesis.

The synthesis of functionalized carbazoles through gold-catalyzed deacylative cycloisomerization of 3-acylindole/ynes is described. A mechanistic proposal for these transformations involving a novel carbonyl group facilitated heterolytic fragmentation upon the loss of an acylium ion intermediate is presented. The eliminated acylium ion species could be trapped by the organogold intermediate to afford acylcarbazoles.