Synthesis of α‐Keto‐1,2,3‐triazoles Through Copper Iodide Catalyzed Oxygenation

Abstract

Benzyltriazoles have been catalytically oxidized by using CuI and tert‐butyl hydroperoxide to yield phenyl(1H‐1,2,3‐triazol‐4‐yl)methanone derivatives in good yields at room temperature.

Chloroacetate‐Promoted Selective Oxidation of Heterobenzylic Methylenes under Copper Catalysis

“…The desired product was isolated as a colorless oil in 65 % yield. 1 3,150.9,142.6,121.2, Received: September 28, 2014 Revised: November 1, 2014 Published online: December 5, 2014 . Keywords: copper catalysis · ethyl chloroacetate · N-heterocycles · selective oxidations…”

“…[2] Traditionally, N-heterocyclic ketones are prepared with stoichiometric quantities of a hazardous oxidant. [3] Meanwhile, this process often produces large amounts of unwanted by-products. Besides, transition-metal-catalyzed oxidations of heterobenzylic methylenes with peroxides have also been developed as an efficient approach toward the synthesis of N-heterocyclic ketones.…”

Unusual Effect of Impurities on the Spectral Characterization of 1,2,3-Triazoles Synthesized by the Cu-Catalyzed Azide–Alkyne Click Reaction

“…For example, cases of “signal disappearance” in the 15 N NMR spectrum due to deprotonation of the amide fragment in the peptide by transition metal ions, as well as the disappearance of two signals in the 13 C spectrum of 1-unsubstituted 1,2,3-triazole due to tautomerism, have been described previously . Incomplete NMR spectra of 1-substituted 1,2,3-triazoles obtained by the click reaction of copper­(I)-catalyzed azide–alkyne cycloaddition were also published, but this effect was not commented upon (see refs − and their corresponding Supporting Information). This is a quite challenging case, which was either not explained or overlap with other signals was assumed.…”

Copper-Catalyzed Oxidative Cross-Dehydrogenative Coupling/Oxidative Cycloaddition: Synthesis of 4-Acyl-1,2,3-Triazoles

“…Among them, 4-acyl-1,2,3-triazoles have drawn particular attention due to their unique biological activities . Some approaches have been disclosed for providing them now such as CuAAC reaction of ynones or acetylenic carbinols with organic azides (Scheme A) and cyclization/oxidation reaction of enones (Scheme B) . Unfortunately, there was the potential polymerization for ynones or enones.…”

“…On the basis of the results above and previous literature reports, a plausible reaction path is outlined (Scheme ). Oxidative coupling of acetophenone with DMF in the presence of Cu­(II)/K 2 S 2 O 8 forms the intermediate 6 , which can eliminate N -methylformamide to give intermediate 7 .…”