Synthesis of Benzothiophene-3-carboxylic Esters by Palladium Iodide-Catalyzed Oxidative Cyclization–Deprotection–Alkoxycarbonylation Sequence under Aerobic Conditions
Raffaella Mancuso, Simona Cuglietta, Romina Strangis, Bartolo Gabriele
Abstract
A palladium-catalyzed carbonylative approach to benzothiophene-3-carboxylic esters, starting from simple and readily available building blocks [2-(methylthio)phenylacetylenes, CO, an alcohol, and O2 (from air)], is reported. The process is catalyzed by the simple PdI2/KI catalytic system to give the desired products in fair to high yields (57–83%). Interestingly, the reaction also works nicely in the ionic liquid BmimBF4 as the solvent, with the possibility to recycle the catalytic system several times without appreciable loss of activity.
Topics & Concepts
ChemistryBenzothiophenePalladiumCatalysisOxidative phosphorylationIodideOrganic chemistrySequence (biology)BiochemistryThiopheneOxidative Organic Chemistry ReactionsSynthesis and biological activityCatalytic C–H Functionalization Methods