Indene Derived Phosphorus-Thioether Ligands for the Ir-Catalyzed Asymmetric Hydrogenation of Olefins with Diverse Substitution Patterns and Different Functional Groups

Identifier:  imarina:9187118

Handle: https://hdl.handle.net/20.500.11797/imarina9187118

Authors:  Margalef, Jessica; Biosca, Maria; de la Cruz-Sanchez, Pol; Caldentey, Xisco; Rodriguez-Escrich, Carles; Pamies, Oscar; Pericas, Miquel A; Dieguez, Montserrat

Abstract:
A family of phosphite/phosphinite-thioether ligands have been tested in the Ir-catalyzed asymmetric hydrogenation of a range of olefins (50 substrates in total). The presented ligands are synthesized in three steps from cheap indene and they are air-stable solids. Their modular architecture has been crucial to maximize the catalytic performance for each type of substrate. Improving most Ir-catalysts reported so far, this ligand family presents a broader substrate scope, covering different substitution patterns with different functional groups, ranging from unfunctionalized olefins, through olefins with poorly coordinative groups, to olefins with coordinative functional groups. alpha,beta-Unsaturated acyclic and cyclic esters, ketones and amides werehydrogenated in enantioselectivities ranging from 83 to 99% ee. Enantioselectivities ranging from 91 to 98% ee were also achieved for challenging substrates such as unfunctionalized 1,1 '-disubstituted olefins, functionalized tri- and 1,1 '-disubstituted vinyl phosphonates, and beta-cyclic enamides. The catalytic performance of the Ir-ligand assemblies was maintained when the environmentally benign 1,2-propylene carbonate was used as solvent.