Pyrrolidine‐Based P,O Ligands from Carbohydrates: Easily Accessible and Modular Ligands for the Ir‐Catalyzed Asymmetric Hydrogenation of Minimally Functionalized Olefins
作者:Pilar Elías‐Rodríguez、Carlota Borràs、Ana T. Carmona、Jorge Faiges、Inmaculada Robina、Oscar Pàmies、Montserrat Diéguez
DOI:10.1002/cctc.201801485
日期:2018.12.7
The potential of P,O‐iminosugar based ligands in the Ir‐catalyzed asymmetric hydrogenation of minimallyfunctionalizedolefins is presented. These new ligands were prepared from easily available carbohydrates (D‐mannose, D‐ribose and D‐arabinose). The stereochemical and polyfunctional diversity of carbohydrates allowed the modulation of the ligands, both from their electronic properties and the rigidity
Alternatives to Phosphinooxazoline (<i>t-</i>
BuPHOX) Ligands in the Metal-Catalyzed Hydrogenation of Minimally Functionalized Olefins and Cyclic β-Enamides
privileged 4‐alkyl‐2‐[2‐(diphenylphosphino)phenyl]‐2‐oxazoline (PHOX) ligands by replacing the phosphine moiety by a biaryl phosphite group and/or the introduction of a methylene spacer between the oxazoline and the phenyl ring. The modular design of the ligands has given us the opportunity not only to overcome the limitations of the iridium‐PHOX catalytic systems in the hydrogenation of minimally functionalized
Phosphite‐thioether/selenoether Ligands from Carbohydrates: An Easily Accessible Ligand Library for the Asymmetric Hydrogenation of Functionalized and Unfunctionalized Olefins
phosphite‐thioether/selenoether ligands has been easily prepared from accessible L‐(+)‐tartaric acid and D‐(+)‐mannitol and applied in the M‐catalyzed (M=Ir, Rh) asymmetrichydrogenation of a broad number of substrates (46 in total). Its highlymodular architecture has been crucial to maximize the catalytic performance. Improving most of the reported approaches, this ligand family presents a broad substrate
Filling the Gaps in the Challenging Asymmetric Hydroboration of 1,1-Disubstituted Alkenes with Simple Phosphite-Based Phosphinooxazoline Iridium Catalysts
ligands efficiently hydroborate a broader range of olefins than previous phosphinooxazoline ligands. In particular, a wide range of α‐tert‐butylstyrenes can be hydroborated that bear aryl substituents with different electronic and steric properties, which complements previous results with N‐heterocyclic copper catalysts, the only other system reported to date that has achieved these reactions.
Extending the Substrate Scope of Bicyclic P‐Oxazoline/Thiazole Ligands for Ir‐Catalyzed Hydrogenation of Unfunctionalized Olefins by Introducing a Biaryl Phosphoroamidite Group
作者:Maria Biosca、Alexander Paptchikhine、Oscar Pàmies、Pher G. Andersson、Montserrat Diéguez
DOI:10.1002/chem.201405361
日期:2015.2.16
This study identifies a series of Ir‐bicyclic phosphoroamidite–oxazoline/thiazole catalytic systems that can hydrogenate a wide range of minimallyfunctionalizedolefins (including E‐ and Z‐tri‐ and disubstituted substrates, vinylsilanes, enol phosphinates, tri‐ and disubstituted alkenylboronic esters, and α,β‐unsaturated enones) in high enantioselectivities (ee values up to 99 %) and conversions.