Recent Developments on Hemilabile P,O-Type Ligands in Cross-Coupling Reactions

Abstract

This review describes the concepts of and recent developments on monophosphine P,O-type ligands. The attractive synthetic pathways to these ligands are highlighted, and the applications of the ligands in cross-coupling reactions are fully illustrated. The hemilabile properties of P,O-type ligands on complexation with transition metals are also discussed.

Nickel fluoro complexes as intermediates in catalytic cross-coupling reactions

“…There is some precedent in the literature which suggests that complexes bearing hemilabile coordinating ligands can catalyse cross-coupling reactions in a more efficient way than related monodentate counterparts [48]. Thus, Milstein et al compared the ligand properties of the hemilabile coordinating phosphine di-tertbutyl(2,6-dimethoxybenzyl)phosphine (dmobp) with these of ditert-butyl-(2,4,6-trimethylbenzyl)phosphine (tmbp) [49].…”

Cationic versus Anionic Palladium Species in the Suzuki–Miyaura Cross‐Coupling

“…[13] Furthermore, (C^N)-chelating NHC ligands for palladium have proven their effectiveness in cross-coupling reactions, [14] either by directly stabilizing the catalyst or by their potential hemilability, allowing them to stabilize labile and otherwise low-coordinate intermediates. [15] Among these, palladium complexes with chelating pyrimidylimidazolin-2-ylidene ligands have been successfully employed in various catalytic reactions. [16] In 2009, we reported complex 1, containing both a palladium cation and a palladium anion (Scheme 1).…”

Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

“…Such a behaviour, which was shown to have a deep impact on the catalyst performance, is classically observed with very bulky monophosphines [1,7–10], including dendrimeric ones [11–12], and is also found with hybrid ligands displaying hemilability so as to prevent the coordination of a second phosphorus atom [13–14] or cavity-shaped phosphines [15]. The use of sterically-hindered P(III)-derivatives, notably phosphites [16–21], has also proven beneficial in yet another carbon–carbon forming reaction, namely the rhodium-catalysed hydroformylation [22] of α-olefins [23–29].…”