A simple, mild method for the oxidation of α-trifluoromethyl alcohols to trifluoromethyl ketones (TFMKs) using the oxoammonium salt 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (1) is described. Under basic conditions, oxidation proceeds rapidly and affords good to excellent yields of TFMKs, without concomitant formation of the hydrate. The byproduct of the oxidation, 4-acetylamino-2,2,6,6-tetramethyl-1-piperidinyloxy (1c), is easily recovered and can be conveniently reoxidized to regenerate the oxoammonium salt.
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http://dx.doi.org/10.1021/jo301477s | DOI Listing |
J Am Chem Soc
November 2024
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.
Hydride abstraction represents a promising yet underexplored approach in the functionalization of C-H bonds. In this work, we report the oxidation of α-C-H bonds of ethers via oxoammonium catalysis using 3-chloroperbenzoic acid (CPBA) as the terminal chemical oxidant or by means of electrochemistry. Mechanistic studies revealed intricate equilibria and interconversion events between various catalytic intermediates in the presence of CPBA, which alone however was incompetent to drive catalytic turnover.
View Article and Find Full Text PDFOrg Lett
August 2024
Discovery Chemistry, Janssen Research & Development, LLC, Spring House, Pennsylvania 19477, United States.
On-DNA carboxylic acids are important synthetic intermediates in the synthesis of DNA-encoded library (DEL) structures. Herein, we report an oxoammonium salt-mediated, room temperature, solution-phase oxidation of DNA-linked primary alcohols into carboxylic acids. This method exhibits a wide substrate scope, encompassing aliphatic, benzylic, and heterobenzylic alcohols, and is compatible with DEL encoding strategies.
View Article and Find Full Text PDFJ Org Chem
April 2024
Department of Biological and Chemical Sciences, College of Life Sciences, Thomas Jefferson University, 4201 Henry Ave, Philadelphia, Pennsylvania 19144, United States.
Aromatic diazenes are often prepared by oxidation of the corresponding hydrazides using stoichiometric quantities of nonrecyclable oxidants. We developed a convenient alternative protocol for the oxidation of aromatic hydrazides using Bobbitt's salt (), a metal-free, recyclable, and commercially available oxoammonium reagent. A variety of aryl hydrazides were oxidized within 75 min at room temperature using the developed protocol.
View Article and Find Full Text PDFJ Am Chem Soc
February 2024
Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States.
Nidulaxanthone A is a dimeric, dihydroxanthone natural product that was isolated in 2020 from . Structurally, the compound features an unprecedented heptacyclic 6/6/6/6/6/6/6 ring system which is unusual for natural xanthone dimers. Biosynthetically, nidulaxanthone A originates from the monomer nidulalin A via stereoselective Diels-Alder dimerization.
View Article and Find Full Text PDFJ Org Chem
February 2024
Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China.
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