Ligand‐Dependant Selective Synthesis of Mono‐ and Dialkenylcarbazoles through Rhodium(III)‐Catalyzed C−H Alkenylation

Abstract

AbstractThe C−H alkenylation of N‐acetylcarbazoles proceeds smoothly at the C1‐position in the presence of a cationic Cp*Rh(III) catalyst to produce 1‐alkenylcarbazoles. The use of a cationic CpERh(III) catalyst enables further alkenylation to give 1,8‐dialkenylcarbazoles. The direct alkenylation procedure in combination with the ready removal of the acetyl directing group provides a straightforward synthetic pathway to 1‐ and/or 8‐alkenyl‐N‐H‐carbazole derivatives. One of 1‐alkenyl‐N‐H‐carbazoles obtained by the present C−H alkenylation/deacetylation exhibits solvatochromism.