Chemoselective Oxidation of Benzyl, Amino, and Propargyl Alcohols to Aldehydes and Ketones under Mild Reaction Conditions

Abstract

Catalytic oxidation reactions often suffer from drawbacks such as low yields and poor selectivity. Particularly, selective oxidation of alcohols becomes more difficult when a compound contains more than one oxidizable functional group. In order to deliver a methodology that addresses these issues, herein we report an efficient, aerobic, chemoselective and simplified approach to oxidize a broad range of benzyl and propargyl alcohols containing diverse functional groups to their corresponding aldehydes and ketones in excellent yields under mild reaction conditions. Optimal yields were obtained at room temperature using 1 mmol substrate, 10 mol % copper(I) iodide, 10 mol % 4-dimethylaminopyridine (DMAP), and 1 mol % 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) in acetonitrile, under an oxygen balloon. The catalytic system can be applied even when sensitive and oxidizable groups such as alkynes, amines, and phenols are present; starting materials and products containing such groups were found to be stable under the developed conditions.

Recent Advances in Molecular Oxygen Assisted Laccase Catalyzed Sustainable Organic Transformations

“…The oxidation of propargylic alcohols to respective α, β ‐Acetylenic carbonyl compounds, [27a] and ynones are important precursors in organic synthesis. In contrast to other traditional oxidative methods, laccase‐mediated oxidation has been shown to be a sustainable oxidative method for the generation of propargylic ketones.…”

Versatile Sulfathiazole-Functionalized Magnetic Nanoparticles as Catalyst in Oxidation and Alkylation Reactions

“…Low yields and poor selectivity have been the main drawbacks associated with catalytic oxidation reactions. Recently, the selective oxidation of benzyl alcohols to benzaldehyde by using iron oxide-based nanocomposites [17], ionic liquid-modified MIL-100(Fe) [18], developed copper(Ι)/TEMPO catalysts (TEMPO = 2,2,6,6-tetramethylpiperidinyl-N-oxyl) [19,20], photocatalytic oxidation by homogeneous CuCl2 [21], metal-free systems [22], photoactive VO@g-C3N4 [23] and Co oxide nanoparticles [24], among others have been reported.…”