Aryl Difluoromethyl Research Articles

A simple convenient method for preparation of difluoromethyl ethers using fluorosulfonyldifluoroacetic acid as a difluorocarbene precursor

In the presence of catalytic amounts of sodium sulfate or cuprous iodide, a variety of alkyl and aryl difluoromethyl ethers were synthesized in moderate yields by the reaction of the corresponding alcohols and phenols with fluorosulfonyldifluoroacetic acid ( 1 ) in acetonitrile under mild conditions. Fluorosulfonyldifluoroacetate anion [FO 2SCF 2OC 2 -] ( 5 ) is believed to readily eliminate SO 2, CO 2 and F -, thus liberating CF 2:; insertion of difluorocarbene into O-H bonds and its capture by fluoride ion then result in the formation of ethers and by-product CF 3H, respectively.

ChemInform Abstract: Improvement of the Synthesis of Aryl Difluoromethyl Ethers and Thioethers by Using a Solid‐Liquid Phase‐Transfer Technique.

Abstract A new solid-liquid phase-transfer technique has been used to synthesize aryl difluoromethyl ethers and thioethers. Phenols (or thiophenols) and chlorodifluoromethane, dissolved in a cheap aprotic solvent of low polarity, are contacted with solid sodium hydroxide in the presence of a catalytic amount of tris-(3,6-dioxaheptyl)amine. The work-up of the reaction mixtures is very simple. Although yields are similar in both homogenous and heterogeneous procedures using phenols, improved yields are obtained for thiophenols when using phase-transfer conditions.

Improvement of aryl difluoromethyl ethers and thioethers synthesis by using a new solid-liquid phase transfer catalyst

Aryl difluoromethyl ethers and thioethers have been synthesized, in the 60s, by reacting a phenol (or a thiophenol) on chlorodifluoromethane, in the presence of a strong base (NaOH, RONa) and a protic medium (H 2O/dioxane, ROH). A difluorocarbene is involved. However, this homogeneous procedure suffers from several limitations: 1. extreme sensitivity of raw aryl difluoromethyl ethers and thioethers to traces of aqueous acids, making the work-up tricky, 2. tedious elimination and recycling of dioxane. So, we have developed a solid-liquid phase-transfer technique to circumvent these drawbacks. Phenols (or thiophenols) and chlorodifluoromethane, dissolved in a cheap aprotic solvent of low polarity, are contacted with solid caustic soda, in the presence of a new phase-transfer agent, really catalytic. Only filtration and distillation are needed. If results are similar in both homogeneous and biphasic procedures for phenols, improved yields are obtained for thiophenols using phase transfer conditions. This observation is consistent with the presence of an aprotic solvent. Several exemples with substituted phenols and thiophenols are given.

Nuclear Magnetic Resonance Spectra of Aryl Difluoromethyl Ethers

Nuclear Magnetic Resonance Spectra of Aryl Difluoromethyl Ethers

Synthetic Applications of Difluorocarbene I. The Preparation of Some Aryl Difluoromethyl Ethers, Thioethers and Sulphones

AbstractAs an extension of the analogous synthesis of aryl difluoromethyl ethers, difluorocarbene. generated from the basic hydrolysis of chlorodifiuoromethane in aqueous dioxane, is brought into reaction with thiophenols, yielding aryl difluoromethyl thioethers.Further conversions lead to the m‐ and p‐difiuoromethoxy‐, difluoro‐methylthio‐ and difluoromethylsulphonyl‐substituted benzoic acids.The chemical stability of the difluoro substituents is discussed and compared with the analogous trifluoro substituents.Phenoxide and thiophenoxide ions are considered as “ambident carbenophiles” in their reaction with dihalocarbenes.

Preparation of aryl difluoromethyl ether, thioether and sulphone derivatives. Electronic properties of the difluoromethoxy, -methylthio and -methylsulphonyl substituents.

Preparation of aryl difluoromethyl ether, thioether and sulphone derivatives. Electronic properties of the difluoromethoxy, -methylthio and -methylsulphonyl substituents.

The Preparation of Aryl Difluoromethyl Ethers1

The Preparation of Aryl Difluoromethyl Ethers¹