Proline-Based P,O Ligand/Iridium Complexes as Highly Selective Catalysts: Asymmetric Hydrogenation of Trisubstituted Alkenes
作者:Denise Rageot、David H. Woodmansee、Benoît Pugin、Andreas Pfaltz
DOI:10.1002/anie.201104105
日期:2011.10.4
O joins the mix: P,O ligands (L1) form efficient iridiumcatalysts for the asymmetric hydrogenation of olefins. The proline‐derived ligands lead to high enantioselectivities with several classes of alkenes, most notably with α,β‐unsaturated carboxylic esters and ketones, where they match or even surpass the ee values reported for the best N,P and C,N ligands.
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
Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Esters with Chiral Iridium N,P Ligand Complexes
作者:David H. Woodmansee、Marc-André Müller、Lars Tröndlin、Esther Hörmann、Andreas Pfaltz
DOI:10.1002/chem.201202397
日期:2012.10.22
Enantioselective conjugate reduction of a wide range of α,β‐unsaturated carboxylicesters was achieved using chiral Ir N,P complexes as hydrogenation catalysts. Depending on the substitution pattern of the substrate, different ligands perform best. α,β‐Unsaturated carboxylicesters substituted at the α position are less problematic substrates than originally anticipated and in some cases α‐substituted