Photostimulated Intramolecular S_RN1 Reaction of Diarylamines to Carbazoles

Significance

The synthesis of a series of 9H-carbazoles is reported by a photostimulated S_RN1 ­intramolecular cyclization of biarylamines which were obtained via palladium- or copper-catalyzed aminations with 2-haloanilines. The reaction was carried out under standard conditions in either liquid ammonia or DMSO in the presence of KOt-Bu to give products in high yields. The substrate scope was not widely studied although the prediction that ”many substituents should be compatible under the reaction conditions" was made.