The chiral boronate-catalyzed asymmetric transfer hydrogenation of various aromatic ketones to high-value alcohols: Preparation and spectroscopic studies

Publication date: Available online 27 March 2019Source: Journal of Organometallic ChemistryAuthor(s): Ahmet Kilic, Mustafa Durgun, Feyyaz Durap, Murat AydemirAbstractThis work deals with the synthesis, spectroscopic studies and catalytic evaluation of the novel chiral salen (L1H2) and (L2H2) ligands and their chiral boronate [L1(B1-4)] and [L2(B1-4)] complexes. Initially, the reaction of 5-azidomethyl salicylaldehyde and (R)-(−)-2-amino-1-butanol in absolute ethanol afforded a new chiral salen ligand (L1H2). Then, a novel chiral salen ligand (L2H2) have been prepared from chiral salen ligand (L1H2) for the synthesis of boronate [L2(B1-4)] complexes through click reaction approach under ambient conditions. The reaction of chiral salen (L1H2) and (L2H2) ligands with various boronic acids afforded a new tetra-coordinated mononuclear chiral boronate [L1(B1-4)] and [L2(B1-4)] complexes. All the compounds are remarkably stable crystalline solids and were obtained in good yields. For the full characterization of newly synthesized chiral salen ligands and their boronate complexes, the FT-IR, UV–Vis, NMR (1H, 13C, and 11B), LC-MS, and elemental analysis techniques have been used. The well-shaped chiral boronate compounds were investigated as catalyst for the asymmetric transfer hydrogenation (ATH) of aromatic ketones under appropriate settings. Particularly, it was proved that the ferrocene-based boronate compounds can afford an efficient catalytic conversion compared to the other...

Source: Journal of Organometallic Chemistry - March 28, 2019 Category: Chemistry Source Type: research