Convenient Synthesis of Alkenyl‐, Alkynyl‐, and Allenyl‐Substituted Imidazo[1,2‐<i>a</i>]pyridines <i>via</i> Palladium‐Catalyzed Cross‐Coupling Reactions

Abstract

Abstract A systematic study on the Stille and Sonogashira cross‐coupling of iodinated imidazo[1,2‐ a ]pyridines was performed, permitting the preparation of various vinyl‐, ethynyl‐, and allenyl‐substituted derivatives. These methods are particularly valuable, given their experimental simplicity and high degree of flexibility with regard to functional groups that can be introduced in positions 3, 6, or 8 of the imidazo[1,2‐ a ]pyridine core. Effects concerning different substitution positions and the nature of the 2‐substituent under various reaction conditions are reported in detail for the above types of unsaturated groups introduced.