Palladium-catalyzed Heck cyclization/carbonylation with formates: synthesis of azaindoline-3-acetates and furoazaindolines.

We report herein a palladium-catalyzed domino cyclization/carbonylation to access ester-functionalized azaindolines, applying formates as a convenient carbonyl source. All four azaindoline isomers were constructed, exhibiting good functional group compatibility. On this basis, modifying the starting tether on the aminopyridine led to furoazaindolines an intramolecular reductive cyclization after the palladium-catalyzed process.