Directed C–H Functionalization of C3-Aldehyde, Ketone, and Acid/Ester-Substituted Free (NH) Indoles with Iodoarenes <i>via</i> a Palladium Catalyst System
Yunus Taskesenligil, Murat Aslan, Tuba Cogurcu, Nurullah Saraçoğlu
Abstract
-protected 3-acetylindoles afforded C4-arylation products without migration of the acetyl group. Functionalization of indole-3-carboxylic acid (or methyl ester) with aryl iodides using the present Pd(II)-catalyst system resulted in decarboxylation followed by the formation of C2-arylated indoles. Based on the control experiments and the literature, plausible mechanisms are proposed. The synthetic utilities of these acetylindole derivatives have also been demonstrated. Remarkably, C4-arylated acetylindoles have allowed the construction of functionalized pityiacitrin (a natural product).
Topics & Concepts
ChemistryArylAldehydeCatalysisSurface modificationDecarboxylationPalladiumKetoneOrganic chemistryIndole testCarboxylic acidCombinatorial chemistryMedicinal chemistryAlkylPhysical chemistryCatalytic C–H Functionalization MethodsSynthesis and Catalytic ReactionsSynthesis of Indole Derivatives