A general method for the preparation of 2,3,5-trisubstituted-furo[3,2-b]pyridines

The preparation of 2,3,5-trisubstituted-furo[3,2-b]pyridines via a Pd(0)-catalyzed intramolecular cyclization of methyl 4-(6-chloro-2-iodopyridin-3-yloxy)-substituted-butenoates 9a–f is described. This approach was both efficient and general, and provided the highly functionalized heterocyclic ring system in high yield. Among the several examples provided is the preparation of 3-[2-(N,N-dimethylamino)ethyl]-5-(4-fluorobenzoyl)amino-2-methylfuro[3,2-b]pyridine 4, a selective 5-HT1F receptor agonist.