Synthesis of [a]Annulated Carbazoles from Indol-2(3H)-one

All articles of this category Reaction of ethyl chloroformate with 3-(2-aryl-1-hydroxyethylidene)indol-2(3 H )-ones 3 affords the corresponding ethyl 3-[(2-aryl-1-ethoxycarbonyloxy)ethenyl]-2-(ethoxycarbonyloxy)indole-1-carboxylates 4 from which ethyl 6-(ethoxycarbonyloxy)-11 H -benzo[ a ]carbazole-11-carboxylates 5a,b , the corresponding 3 H ,10 H -pyrrolo[3,2- a ]- 5c , 10 H -thieno[3,2- a ]- 5d and 10 H -thieno [2,3- a ]carbazole-10-carboxylate 5e are obtained via 6π-electrocyclization.