| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 40758 | Applied Catalysis A: General | 2012 | 10 Pages |
A highly efficient, selective and green catalytic protocol for open air oxidation of primary benzylic alcohols into aldehydes by in situ made N-isopropyl-3,5-di-tert-butylsalicylaldimine (HL3)–Cu(II) complexes and TEMPO (2,2,6,6-tetramethyl-piperidinyloxyl radical) is introduced herein. Distilled water as a solvent the reaction proceeds at 80 °C temperature without any auxiliarities such as base and/or co-solvent. For example, benzyl alcohol is quantitatively and selectively oxidized to benzaldehyde within a few hours under optimized reaction conditions [80 °C, open air, 0.3 mol% CuBr2, 2 mol% HL3, 3 mol% TEMPO and 5 mL of distilled water]. Under anaerobic conditions, the catalyst decomposes to a free ligand and Cu2O nanoparticles (diameter >50 nm) via anticipated Cu(I)-hydroxo complex. On the basis of these observations and deuteration studies, a plausible reaction mechanism is proposed for the catalytic system.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (70 K)Download as PowerPoint slideHighlights► A novel water tolerant catalytic system for alcohol oxidation has been developed. ► Various benzylic alcohols converted to aldehydes with high isolated yields. ► Very low loading of catalyst (0.3 mol%) and TEMPO (3 mol%) is required for efficient oxidation. ► Utilization of distilled water and open air compose a green protocol for the reactions.
