A Practical Synthetic Route to Benzofuro[2,3-b]pyridine and Trifluoromethyl-α-carbolines

In situ generated benzofuran-2-amine reacts with 1,3-CCC-dielectrophiles, such as CF₃-containing β-diketones, 3-formylchromone, methyl-2,4-dioxopentanoate and pentafluorobenzaldehyde, and the reaction leads to the formation of benzofuro[2,3-b]pyridine ring system. By using a similar approach 4-trifluoromethyl-α-carbolines were synthesized starting from indole-2-amine.

Iaroshenko V. O.; Groth U.; Kryvokhyzha N. V.; Obeid S.; Tolmachev A. A.; Wesch T.
Synlett 2008, 03, 343-346
DOI: 10.1055/s-2008-1032042