Trifluoromethyl ethers – synthesis and properties of an unusual substituent

• Frédéric R. Leroux,
• Baptiste Manteau,
• Jean-Pierre Vors and
• Sergiy Pazenok

Beilstein J. Org. Chem. 2008, 4, No. 13, doi:10.3762/bjoc.4.13

• works well with electron-deficient anisoles cannot be applied to anisole itself. In fact, halogen attack on the phenyl ring proceeds more easily than radical chlorination of the methyl group. Louw and Franken could show that with elemental chlorine, photostimulated in refluxing tetrachloromethane

• , essentially trichloromethylanisole is obtained [20]. The fluorination of the trichloromethyl ether succeeds then easily as shown above. The chlorination/fluorination sequence described above can be simplified by producing the trichloromethyl aryl ethers without isolation and through in situ conversion into

• developed an approach based on the readily accessible, although highly toxic aryl chlorothionoformates 1. They can be cleanly converted by chlorination into trichloromethyl aryl ethers [17]. This step is then followed by fluorination using antimony trifluoride and a catalytic amount of antimony

Development of potential manufacturing routes for substituted thiophenes – Preparation of halogenated 2-thiophenecarboxylic acid derivatives as building blocks for a new family of 2,6-dihaloaryl 1,2,4-triazole insecticides

• John W. Hull Jr.,
• Duane R. Romer,
• David E. Podhorez,
• Mezzie L. Ash and
• Christine H. Brady

Beilstein J. Org. Chem. 2007, 3, No. 23, doi:10.1186/1860-5397-3-23

• /debromination procedure developed for 3-methylthiophene gave 2,4-dibromo-3-methylthiophene. Carboxylic acid functionality was then introduced either by a Grignard metallation followed by carbonation with CO2, or by a palladium catalyzed carbonylation procedure under CO pressure. The vapor phase chlorination of

• thiophene ring without isolation of the tribromo intermediate 6. The final low-melting acid chloride 1 was readily purified by vacuum distillation on a 250 g laboratory scale to remove a small amount of tar and gave 1 as a light-yellow colored product. Vapor Phase Chlorination Studies. Routes to 3,4,5

• from 2-chloromethyl-3,4,5-trichlorothiophene. [21] However, since 2-thiophenecarbonitrile 20 was commercially available, we investigated the vapor phase chlorination of this starting material as a potential convenient manufacturing route to 3 that could be carried out on a multi-Kg scale (Scheme 3