P,N,O type chiral imino- and aminophosphine ligands and their applications in Ru(II)-catalyzed asymmetric transfer hydrogen reactions

[Display omitted] •P,N,O type chiral imino- and aminophosphine ligands were synthesized.•Ligands were characterized by spectroscopic techniques such as NMR, FTIR, HRMS and X-Ray.•Ru(II)-catalyzed asymmetric transfer hydrogen reactions were investigated with these ligand systems. Chiral P,N,O type im...

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Bibliographic Details
Published in:Inorganica Chimica Acta 2021-01, Vol.514, p.120022, Article 120022
Main Authors: Keleş, Mustafa, Yılmaz, Mustafa Kemal, İnce, Simay, Keleş, Hülya, Ünver, Hakan
Format: Article
Language:English
Subjects:
Aminophosphine
Asymmetric transfer hydrogenation
Asymmetry
Chemical reactions
Chiral ligand
Crystal structure
Electrons
Ethanol
Iminophosphine
Ketones
Ligands
NMR
Nuclear magnetic resonance
Ruthenium
Ruthenium compounds
Single crystals
Substitutes
X-ray crystallography
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Summary:[Display omitted] •P,N,O type chiral imino- and aminophosphine ligands were synthesized.•Ligands were characterized by spectroscopic techniques such as NMR, FTIR, HRMS and X-Ray.•Ru(II)-catalyzed asymmetric transfer hydrogen reactions were investigated with these ligand systems. Chiral P,N,O type imino- (1a-d) and aminophosphine ligands (2a-d), substituted with methyl-, isopropyl-, phenyl- and benzyl groups, were synthesized and characterized by spectroscopic techniques such as NMR, FTIR and HRMS. The structure of the ligand 1c was also determined by single crystal X-ray diffraction analysis. The X-ray data revealed that compound 1c exhibited triclinic-P1 space group with C40H34NOP molecular formula. The catalytic performances of these imino- and aminophosphine ligands were tested in ruthenium catalyzed asymmetric transfer hydrogenation of aromatic ketones in 2-propanol. Ruthenium(II) complexes were generated in situ from Ru(cod)Cl2, Ru(dmso)4Cl2, Ru(PPh3)3Cl2 and [Ru(p-cymene)Cl2]2 precursors. According to the chromatographic analyses, isopropyl- substituted chiral aminophosphine ligand 2-((2-(diphenylphosphinyl)benzyl)amino)-3-methyl-1,1-diphenylbutan-1-ol (2b) and [Ru(cod)Cl2] combination were found to be the best catalyst system, affording (R)-enriched 1-(4-bromophenyl)ethanol in 85% ee and 98% conversion.
ISSN:0020-1693
1873-3255
DOI:10.1016/j.ica.2020.120022