Multicomponent Synthesis of Benzothiophen‐2‐acetic Esters by a Palladium Iodide Catalyzed S‐cyclization – Alkoxycarbonylation Sequence

A catalytic carbonylative approach to the multicomponent synthesis of benzothiophene derivatives from simple building blocks [1‐(2‐(methylthio)phenyl)prop‐2‐yn‐1‐ols, carbon monoxide, and an alcohol)] is presented. It is based on an S‐cyclization‐demethylation‐alkoxycarbonylation‐reduction sequence promoted by the PdI2/KI catalytic system, occurring under relatively mild conditions (40 atm, 80 °C, 15 h). Benzothiophene‐2‐acetic esters are obtained in moderate to good yields (35–70%) starting from variously substituted substrates in combination with different alcohols as external nucleophiles (17 examples).