Described is a general and efficient synthesis of valuable benzo[b]carbazoles by Brønsted acid-catalyzed reactions between simple C-2,C-3-unsubstituted indoles and ortho-[α-(hydroxy)benzyl]benzaldehyde acetals. Highly selective migration processes are involved as key steps in the overall cascade sequence that involves the one-pot formation of two new bonds and a cycle in a regioselective fashion.
