Facile access to polysubstituted indoles via a cascade Cu-catalyzed arylation-condensation process

Cu(I)/L-proline-catalyzed cross-coupling of 2-halotrifluoroacetanilides with beta-keto esters and amides followed by in situ acidic hydrolysis delivered 2,3-disubstituted indoles. The halides bearing a strong electron-withdrawing group in the 4-position can undergo in situ basic hydrolysis to provide the corresponding indoles. Polysubstituted indoles can be prepared from substituted 2-halotrifluoroacetanilides with high regioselectivity.