Asymmetric Hydrogenation of [alpha],[beta]-Unsaturated Carboxylic Esters with Chiral Iridium N,P Ligand Complexes

• Published in: Chemistry : a European journal Vol. 18; no. 43; p. 13780
• Main Authors: Woodmansee, David H, Müller, Marc-André, Tröndlin, Lars, Hörmann, Esther, Pfaltz, Andreas
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 22-10-2012
• Subjects: Beta; Chemistry
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201202397

Enantioselective conjugate reduction of a wide range of [alpha],[beta]-unsaturated carboxylic esters was achieved using chiral Ir N,P complexes as hydrogenation catalysts. Depending on the substitution pattern of the substrate, different ligands perform best. [alpha],[beta]-Unsaturated carboxylic esters substituted at the [alpha] position are less problematic substrates than originally anticipated and in some cases [alpha]-substituted substrates actually reacted with higher enantioselectivity than their [beta]-substituted analogues. The resulting saturated esters with a stereogenic center in the [alpha] or [beta] position were obtained in high enantiomeric purity. [PUBLICATION ABSTRACT]