Catalytic Oxidation of Alcohols Using a 2,2,6,6‐Tetramethylpiperidine‐N‐hydroxyammonium Cation

Abstract

The oxidation of alcohols to aldehydes, ketones, and carboxylic acids is reported using 2,2,6,6‐tetramethylpiperidine‐4‐acetamido‐hydroxyammonium tetrafluoroborate as a catalyst in conjunction with sodium hypochlorite pentahydrate as a terminal oxidant. The reaction is generally complete within 30–120 min using an acetonitrile/water mix as the solvent, and no additives are required. Product yields are good to excellent and of particular note is that the methodology can be used to access aryl α‐trifluoromethyl ketones.

Copper-Catalyzed Ring-Opening/Reconstruction of Anthranils with Oxo-Compounds: Synthesis of Quinoline Derivatives

“…PE/EtOAc = 30:1; colorless oil, 422.3 mg, 41% yield; 1 H NMR (400 MHz, CDCl 3 ): δ 9.77 (t, J = 1.8 Hz, 1H), 2.43 (td, J = 7.4, 1.8 Hz, 2H), 2.35 (t, J = 7.5 Hz, 1H), 1.30–1.28 (m, 12H); the 1 H NMR spectra data are consistent with the reported literature …”

“…PE/EtOAc = 30:1; colorless oil, 422.3 mg, 41% yield; 1 H NMR (400 MHz, CDCl 3 ): δ 9.77 (t, J = 1.8 Hz, 1H), 2.43 (td, J = 7.4, 1.8 Hz, 2H), 2.35 (t, J = 7.5 Hz, 1H), 1.30−1.28 (m, 12H); the 1 H NMR spectra data are consistent with the reported literature. 39 2-(Thiophen-3-yl)acetaldehyde (4k) (Precursor to Product 5u). PE/EtOAc = 30:1; light yellow oil, 246.0 mg, 24% yield; 1 H NMR (400 MHz, CDCl 3 ): δ 9.74 (t, J = 2.3 Hz, 1H), 7.36 (dd, J = 4.9, 3.0 Hz, 1H), 7.15−7.14 (m, 1H), 6.98 (dd, J = 4.9, 1.2 Hz, 1H), 3.73 (d, J = 2.2 Hz, 2H); 13 C{ 1 H} NMR (101 MHz, CDCl 3 ): δ 198.8, 131.6, 128.5, 126.5, 123.5, 44.9; the 1 H NMR spectra data are consistent with the reported literature.…”

Green Chemistry in der Schule

“…Das Gemisch kann im geschlossenen Gefäß über den Siedepunkt hinaus erhitzt werden, so dass sich die Reaktionszeit im Vergleich zu konventionellen Verfahren erheblich verkürzt. Das Entstehen des Produkts lässt sich an einer leichten Trübung des Reaktionsgemisches erkennen .…”

A one-pot synthesis of benzimidazoles via aerobic oxidative condensation of benzyl alcohols with o-phenylenediamines catalyzed by [MIMPs]+Cl-/NaNO2/TEMPO

“…The aerobic oxidation of alcohols to carbonyl compounds has been intensively investigated. Several TEMPO (2,2,6,6-tetramethylpiperidineoxy)-based transition metal-free catalytic systems have proved to be very efficient for the oxidation of alcohols to aldehydes or ketones with molecular oxygen as the terminal oxidant, 32–43 among which those consisting of acid, nitrite sources, and TEMPO, such as HCl/sodium nitrite (NaNO 2 )/TEMPO and [Imim-TEMPO] + X/[Imim-COOH] + X/NaNO 2 , are the most attractive due to their high efficiency, easy availability, and mild reaction conditions. 36,39 Either HCl or [Imim-COOH] is necessary to convert nitrite into nitrous acid in situ in the catalytic cycles.…”