ABSTRACT A general palladium‐catalyzed Sonogashira cross‐coupling reaction of aryl and heteroaryl chlorides with aliphatic, aryl and heteroaryl alkynes is described. The Pd(dba)₂/ PCy 2 ‐Napdole‐phos catalyst system efficiently promotes the reaction, exhibiting broad substrate scope and excellent functional group tolerance. Notably, the catalyst loading can be down to 0.2 mol% Pd. The PCy 2 ‐Napdole‐phos , featuring an extended π‐system provides substantial steric bulk to facilitate the construction of C(sp 2 )—C(sp) bonds.
Lau et al. (Wed,) studied this question.