A Preperation Of Allylic Trifluoromethyl Thioethers As Building Blocks

Due to the fluorine’s characteristics of the high electronegativity, small atomic pradius and low polarization, the physical and chemical properties and the biological activities of these organic compounds which are introduced to the fluorine will have some unique changes, and this will make the applicational value of the parent compounds get a great improvement in the fields of material, medicine, military and so on. In the numerous of fluorine-containing organic compounds, the organic fluorides containing trifluoromethylthio group are getting more and more attention in recent years. Compare of other fluorine-containing fuctional groups, the structure of trifluoromethylthio group shows us a stronger electron-withdrawing effect and a very higher lipophilicity and biological activity. Therefore, the development of straightforward, efficient and economical synthetic methods for trifluoromethylthio compounds is desirable.On the other hand, because allylic compounds are very useful synthons that can be transformed to varieties of more complex organic molecules, and the compounds which containing allyl groups constitute inimitably useful building blocks as synthons, it is very important and valuable to find an efficient and general approach to the synthesis of allylic trifluoromethyl thioethers.In this paper, a kind of economical, efficient, stable and harmfulless trifluoromethylthiolation reagent was used to react with allylic bromides to produce allyl trifluoromethyl thioethers through the trifluoromethylthiolation reaction. Because of the expensive and instable allylic bromides, a general approach to synthesize variety of them was found from the previous literature. Namely, the common and low-cost aldehyde compounds was used as materials to produce a lot of typical substrates by means of Horner-Wadsworth-Emmons olefination reaction, selective hydrogenation reduction reaction by using DIBAL-H and bromination reaction by using PBr3.According to a series of conditions explored, an optimal facile method was found in this paper, which is that under nitrogen protected and 70℃, with acetonitrile as the solvent, the allylic bromide reacted with 1.2 equivalents [(bpy)CuSCF3] for 8 hours, and successfully proceeded to afford the corresponding products with excellent stereo-and regioselectivity and in good yields. Through the expansion of the substrate, it was found that lots of common functional groups such as alkyl, alkoxy, trifluoromethyl, nitro, geranyl and halides were well tolerated.