2,2,2‐Trifluoroacetophenone as an Organocatalyst for the Oxidation of Tertiary Amines and Azines to N‐Oxides

Abstract

A cheap, mild and environmentally friendly oxidation of tertiary amines and azines to the corresponding N-oxides is reported by using polyfluoroalkyl ketones as efficient organocatalysts. 2,2,2-Trifluoroacetophenone was identified as the optimum catalyst for the oxidation of aliphatic tertiary amines and azines. This oxidation is chemoselective and proceeds in high-to-quantitative yields utilizing 10 mol % of the catalyst and H2 O2 as the oxidant.

Green Organocatalytic Oxidative Methods using Activated Ketones

“…One year later, Kokotos and co‐workers extended the use of 2,2,2‐trifluoroacetophenone as the organocatalyst for the oxidation of tertiary amines and azines to N ‐oxides (Scheme ) . N ‐Oxides are key components for ubiquitously used materials, such as toilet soaps, toothpastes, detergents, shampoos, and cosmetics, and they are also found in products for biomedical applications .…”

One‐Pot Synthesis of O‐Allylhydroxylamines through the Organocatalytic Oxidation of Tertiary Allylic Amines Followed by a [2,3]‐Meisenheimer Rearrangement

“…There is a literature report in which, depending on the oxidation system and the substrate utilized, a mixture of oxidation of amine ( N ‐oxide) and alkene (epoxide) is obtained 3i. Although our oxidation protocol can perform both the oxidation of tertiary amines7b and alkenes,7c in all substrates utilized in this study, no epoxide was detected, thus providing excellent selectivity for the oxidation of tertiary amines (see also the Supporting Information). Initially, a number of dibenzyl allylic amines ( 1 a – d ), bearing mono‐, di‐, or nonsubstituted short and long aliphatic chains8 were tested, providing the corresponding products in very high yields ( 2 a – d ).…”

“…Previously, 2,2,2‐trifluoacetophenone was proven to be the optimum catalyst, among a series of activated ketones, for the organocatalytic oxidation of silanes to silanols 7a. Following our initial contribution, the same catalyst was found to promote both the oxidation of azines and tertiary amines to N ‐oxides7b and olefins to epoxides 7c. Herein, optimization reactions were carried out to establish the optimum conditions for the model reaction of the synthesis of O ‐allyl‐ N , N ‐dibenzylhydroxylamine (Table 1).…”

A heterogeneous organocatalyst for olefin epoxidation

“…In fact, 2-5 mol.% of this molecular organocatalyst epoxidize selectively 20 various olefins with the yields up to 99% using H 2 O 2 as an oxidant and acetonitrile as a stoichiometric co-reagent. Besides, ability of trifluoroacetophenone to perform the oxidation of organosilanes to silanolic species as well as of quaternary amine and azine in the Noxides have been shown in [7,8]. Herein, we report a novel catalytic system based on SBA-15 molecular sieve modified with covalently bonded TFAP species, proven to be efficient for epoxidation of propylene using H 2 O 2 as an oxidant.…”