The recent development of phosphine ligands derived from 2-phosphino-substituted heterocycles and their applications in palladium-catalyzed cross-coupling reactions

Heterocyclic phosphines have long been used as unique and efficient ligands for palladium-catalyzed cross-coupling reactions. The simplest ligand, trifurylphosphine, has become one of the most classical heterocyclic phosphines for coupling reactions since its first application in the Stille coupling reaction in 1988. In recent decades, palladium catalyst systems derived from highly diverse and innovative heterocyclic phosphines have shown excellent catalytic activities in cross-coupling reactions. In this account, we discuss the recent development and applications of heterocyclic phosphine ligands, highlighting the synthetic pathways used to prepare the ligands. The sections are categorized by the different palladium-catalyzed cross-coupling methodologies.