Chiral Olefins as Steering Ligands in Asymmetric Catalysis

Abstract

Metal-catalyzed asymmetric processes offer one of the most straightforward ways to introduce stereogenic centers. Hence, the development of novel chiral ligands that can effectively induce asymmetry in reactions is crucial in modern organic synthesis. While many established chiral ligands bind to a metal through heteroatoms, structures that coordinate to metals through carbon atoms have received little attention so far. Here, we highlight the increasing number of such chiral chelating olefin ligands as well as their application in a variety of metal-catalyzed transformations.

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

“…399 Seminal DFT studies by Qin and Kantchev 400−402 as well as by Brown and Hayashi 403 reported that the conjugate 1,4-addition is thermodynamically preferred over direct 1,2-addition. Moreover, carborhodation was identified as the enantiodetermining step in contrast to previous proposals on enone binding being enantiodiscriminating.…”

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

“…Independently, Carriera and coworkers reported the application of a chiral diene for Ir-catalyzed allylic substitution [105]. These independent discoveries have spurred intense research efforts in homogeneous catalysis which were compiled in 2008 in an excellent review by Carreira and Grützmacher [106]. An examination of the substituent-effect in chiral bicyclo[2 : 2 : 1]heptadiene scaffold revealed that just two methyl groups in ligand L27a are sufficient to impart a high enantioselectivity (95% ee) in the ECA reaction [99].…”

The First General and Selective Palladium(II)‐Catalyzed Alkoxycarbonylation of Arylboronates: Interplay among Benzoquinone‐Ligated Palladium(0) Complex, Organoboron, and Alcohol Solvent

“…[2] In striking contrast, the relevant palladium(II)-catalyzed alkoxycarbonylation of organoboron compounds has remained far less explored, although other palladium-catalyzed transformations of organoboron species such as SuzukiMiyaura and relevant couplings [3] or other reactions [4] have been extensively developed. [5] There exist only few reports on the methoxycarbonylation of vinyland arylboron reagents. [6,7] Miyaura and Suzuki reported for the first time that alkenylborons derived from the hydroboration of alkynes with catecholborane could be transformed into the corresponding methyl acrylates via palladium-catalyzed methoxycarbonylation at ambient temperature.…”