Preactivation-free direct decarboxylative alkynylation of indoleacetic acids: access to alkynyl-functionalized indoles

Abstract

Herein, we report, to the best of our knowledge, the first preactivation-free decarboxylative alkynylation of indoleacetic acids with terminal alkynes via transition-metal catalysis. This protocol operates under mild conditions, forges C(sp³)-C(sp) bonds efficiently without N-hydroxyphthalimide ester preactivation or exogenous oxidants, and exhibits excellent substrate compatibility across diverse indoleacetic acids and terminal alkynes, delivering valuable alkynylated indole products in good to excellent yields. This approach fills a long-standing gap in decarboxylative coupling and provides a practical, atomeconomical synthetic route to alkynyl indole scaffolds for pharmaceutical and materials applications.2