Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
作者:Bram B. C. Peters、Jira Jongcharoenkamol、Suppachai Krajangsri、Pher G. Andersson
DOI:10.1021/acs.orglett.0c04012
日期:2021.1.1
Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir–N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated
An unprecedented ruthenium(II)-catalyzed intramolecularoxidative C–N coupling method has been developed for the facile synthesis of a variety of synthetically challenging tri- and tetrasubstituted pyrazoles. Dioxygen gas is employed as the oxidant in this transformation. The reaction demonstrates excellent reactivity, functional group tolerance, and high yields.
Primary allylic amines with enantiomeric excesses from 97 to >99% were prepared by asymmetric transfer hydrogenation of α,β-unsaturated N-(tert-butylsulfinyl)ketimines followed by removal of the sulfinyl group. The effect caused by different substituents at the C═C bond and at the iminic carbon atom on the chemoselectivity of the reduction was studied. The desired enantiomer of the final allylic amine