Methyl(trifluoro‐methyl)dioxirane

TL;DR: In this paper, the authors describe the preparation of dilute solutions of the reagent in 1,1,1-trifluoro-2-propanone (TFDO) and this ketone as described below.

Abstract: [115464-59-0] C3H3F3O2 (MW 128.06) InChI = 1S/C3H3F3O2/c1-2(7-8-2)3(4,5)6/h1H3 InChIKey = NEGUMGNBGIFXAL-UHFFFAOYAP (selective, reactive oxidizing agent capable of epoxidation of unreactive alkenes5 and arenes,7 oxyfunctionalization of alkanes,3 oxidation of alcohols16 and ethers19) Alternate Name: TFDO. Physical Data: known only as a dilute solution. Solubility: sol in acetone and CH2Cl2; sol in most other organic solvents, but reacts slowly with many of these. Form Supplied in: dilute solutions of the reagent in 1,1,1-trifluoro-2-propanone are prepared from Oxone (Potassium Monoperoxysulfate) and this ketone as described below. Drying: initial drying of reagent solutions is accomplished with reagent grade anhyd MgSO4 in the cold. After filtration, solutions are typically stored over molecular sieves. Analysis of Reagent Purity: concentrations of the reagent can be determined by classical iodometric titration or by reaction with an excess of an organosulfide and determination of the amount of sulfoxide formed by NMR or gas chromatography. Preparative Methods: TFDO solutions are prepared by mixing 1,1,1-trifluoro-2-propanone (TFP) and aqueous buffered Oxone in the cold and collecting the volatile TFDO–TFP mixture by transfer into a cold trap in a stream of inert gas under reduced pressure (eq 1).3 (1) Handling, Storage, and Precautions: solutions of the reagent can be kept in the freezer of a refrigerator at −20 °C for as long as a week. The concentration of the reagent decreases relatively slowly (ca. 6–8% in 48 h), provided solutions are properly stored. It is particularly important that solutions be kept from light and traces of heavy metals, since the reagent is particularly susceptible to their influence. These dilute solutions are not known to decompose explosively, but the usual precautions for handling peroxides should be applied, including the use of a shield. All reactions should be performed in a hood to avoid exposure to the powerful, volatile oxidant.