Density Functional Studies on Palladium‐Catalyzed Suzuki–Miyaura Cross‐Coupling Reactions Assisted by N‐ or P‐Chelating Ligands

Abstract

DFT studies with the B3LYP functional have been carried out on the Suzuki-Miyaura cross-coupling reactions of phenyl chloride and phenylboronic acid catalyzed by palladium complexes with N- or P-chelating ligands. The full catalytic cycle, from the addition of reactants to the catalyst to the release of the cross-coupled product from the complexed intermediate, has been examined. The stages within the cycle, such as oxidative addition, transmetalation, and reductive elimination, were validated by linking the mechanistically relevant intermediates and transition states. Various derivatives of diimine, diphosphine, and diamine were considered as potential model ligands. The catalytic reaction employing diimine as the chelating ligand has been verified as the one with the most energetically feasible route.

Mechanistic study on iron(II)‐mediated direct arylation of benzene with chlorobenzene

“…It was the fact that the metal species tend to react preferentially with C‐Cl bond rather than the more inert C‐H bonds. This is not only in line with the thermodynamics that the bond energy of C‐Cl (397 kJ/mol) in chlorobenzene is less than C‐H (477 kJ/mol) in benzene but also accords with previous studies such as Heck coupling, cross‐coupling (Stille, Negishi, Suzuki‐Miyaura) . This could also interpret well that only in a few cases, trace amounts of biphenyl resulting from the coupling of two benzene molecules were detected experimentally .…”

Mechanistic pathways for oxidative addition of aryl iodides to the low-ligated diethanolamine palladium(0) complex in phosphine-free Heck reactions

“…In bI2 Pd is coordinated with Cl and the C2-C3 bond, which is documented with the delocalization of the sp 2.41 orbital of Cl (whose occupancy is 1.80) into the formally empty sp 0.05 d 0.08 orbital of Pd (whose occupancy is 0.27), and the delocalization of a d orbital of Pd (whose occupancy is 1.69) into the p * antibonding of bTS4 and I4 is that Pd exhibits a distorted trigonal coordination (Table 3). Tricoordinated Pd complexes are known in literature [15,16,[21][22][23]. In bTS4 the weak Pd-C1 bond is formed.…”

“…This step has been the subject of much investigation [14][15][16][17][18][19][20][21], and is considered to be the rate determining process. Oxidtive addition usually involves coordinatively unsaturated Pd(0) complexes [15][16][17][21][22][23]. A lot of work has been devoted to the elucidation of the catalytic pathways where phosphines are used as ligands [14][15][16][17][18][22][23][24], whereas the results regarding non-phosphine ligands are scarced [19,20,[25][26][27][28][29][30][31].…”

Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals

“…This reaction is commonly described in the literature by two standard catalytic cycles that differ according to the nature of the palladium intermediate, neutral or anionic [39]. Both cycles involving Pd(0)/Pd(II) complexes are commonly accepted by the scientific community and have been widely explored in experimental [22] and computational [53,54,55] studies.…”