title: A versatile Ru catalyst for the asymmetric transfer hydrogenation of both aromatic and aliphatic sulfinylimines.
abstract: A highly efficient Ru catalyst based on an achiral, very simple, and inexpensive amino alcohol ligand (2-amino-2-methylpropan-1-ol) has been developed for the asymmetric transfer hydrogenation (ATH) of chiral N-(tert-butylsulfinyl)imines. This complex is able to catalyze the ATH of both aromatic and the most challenging aliphatic sulfinylimines by using isopropyl alcohol as the hydrogen source. The diastereoselective reduction of aromatic, heteroaromatic, and aliphatic sulfinylketimines, including sterically congested cases, over short reaction times (1-4 h), followed by desulfinylation of the nitrogen atom, affords the corresponding highly enantiomerically enriched (ee up to >99 %) α-branched primary amines in excellent yields. The same ligand was equally effective for the synthesis of both (R)- and (S)-amines by using the appropriate absolute configuration in the iminic substrate. DFT mechanistic studies show that the hydrogen-transfer process is stepwise. Moreover, the origin of the diastereoselectivity has been rationalized.
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias and Instituto de Síntesis Orgánica, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
authors.forename: Óscar
authors.initials: Ó
authors.lastname: Pablo
authors.forename: David
authors.initials: D
authors.lastname: Guijarro
authors.forename: Gábor
authors.initials: G
authors.lastname: Kovács
authors.forename: Agustí
authors.initials: A
authors.lastname: Lledós
authors.forename: Gregori
authors.initials: G
authors.lastname: Ujaque
authors.forename: Miguel
authors.initials: M
authors.lastname: Yus
mesh_terms: D002384:Catalysis; D006865:Hydrogenation; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism; D013441:Sulfinic Acids / Q000737:chemistry*
chemical_list: D007097:Imines; D013441:Sulfinic Acids; D012428:Ruthenium