Quantifying the Electronic Effect of C4 and C4′ Positions of Bipyridine Ligand on Pd(II)/Rh(I)‐Catalyzed Conjugate Addition Reaction: A DFT Study

Abstract

AbstractThe electronic effects of the bidentate ligands play a vital role in the transition metal‐catalyzed conjugate addition reactions. Here, the insertion step (rate‐determining step (RDS) of the conjugate addition) catalyzed by Pd(II)/Rh(I)‐complexes with 26 bipyridine‐type (bpy) ligands linking different substituent groups in the opposite sides (C4, C4′ position) are systematically studied by density functional theory (DFT). It is found that for both Pd(II)‐ and Rh(I)‐catalysis, the stronger the electron‐withdrawing group connecting to both C4 and C4′ positions of bpy ligands can promote the insertion step. The predominance of π‐back donation in Rh(I) and σ‐donation in Pd(II) is the main reason for above different electronic properties of Pd(II) and Rh(I)‐catalysis. This work gives enough theoretical guide to the rational design of the efficient transition metal‐based catalyst for conjugate addition.