Hidden Enantioselective Hydrogenation of N-Silyl Enamines and Silyl Enol Ethers in Net C:N and C:O Hydrosilylations Catalyzed by Ru-S Complexes with One Monodentate Chiral Phosphine Ligand was written by Baehr, Susanne;Oestreich, Martin. And the article was included in Organometallics in 2017.SDS of cas: 134484-36-9 This article mentions the following:
Ruthenium thiolate complexes with one chiral monodentate phosphine ligand are applied to enantioselective hydrosilylation of enolizable imines and ketones. The structural features of the catalyst exclude the presence of more than one phosphine ligand at the ruthenium center in the enantioselectivity-determining step. The enantiomeric excesses obtained in these reduction reactions are moderate (up to 66% ee), but the stereochem. outcome enables an exptl. anal. of the reaction pathways operative in this catalysis. A two-step sequence consisting of successive N-Si/O-Si dehydrogenative coupling and enamine/enol ether hydrogenation is the prevailing mechanism of action. Both steps involve cooperative bond activation at the Ru-S bond of the coordinatively unsaturated ruthenium complex: Si-H bond activation in the dehydrogenative coupling and heterolytic H-H splitting in the hydrogenation. Previously documented side reactions such as deprotonation/protonation equilibrium as well as competing direct C:N or C:O hydrogenation have been excluded. In the experiment, the researchers used many compounds, for example, (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9SDS of cas: 134484-36-9).
(S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9) belongs to chiral phosphine ligands. Phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.SDS of cas: 134484-36-9
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis