Halogen-Exchange Fluorination of Primary Alkyl Halides Using 1B Metal Fluorides-Pyridine Derivatives

Abstract

Deep purplish red semicrystaline precipitates were obtained by the treatment of Cu2O with HF. After calcination at 100 °C or higher temperature, this compound was successfully used as a highly effective halogen-exchange fluorination reagent for primary alkyl halides in the presence of pyridine derivatives. AgF and a mixture of CuF2 with copper powder also exhibited high activity in the reaction.

Catalytic Fluorination by Halide Exchange with 16-Electron Ruthenium(II) Complexes. X-ray Structure of [Tl(μ-F)2Ru(dppe)2]PF6

“…Thus, nearly quantitative conversions and selectivities up to 88% for the fluorinated products are obtained. The present system also reacts with less activated haloalkanes than required by silver and copper florides . Moreover, kinetic resolution takes place, albeit with a low efficiency, as racemic 6a gives slightly enantiomerically enriched Ph(Me)CHF in the reaction with the chiral catalyst 2 .…”

Recent advances in the selective formation of the carbon-fluorine bond

“…Finally Cu20 / anhydrous HF mixtures have been used in halogen exchange fluorination reactions for making cyclo and tertiary alkyl fluorides.21 With primary halides, elimination was the major pathway, but this has been overcome by using a deep purple solid which was isolated from Cu20 and anhydrous HF at low temper- atures, and is thought to be of the composition CuF-0.5H2O. 22 This compound is stable at room temperature and when used in combination with 2,2/-bipyridine or collidine gave high yields of primary alkyl fluorides. This halogen exchange reaction was found to be superior to the more traditional reagents such as spray-dried KF or anion resins.…”

Versatile Reactivity and Catalytic Effects of Copper(II) Halides in Organic Syntheses

“…On the use of CuF 2 in acetonitrile, with refluxing at 82 °C for 128 h, the halogen-exchanged fluorination of primary alkyl halides gave, for example, the 1-fluorooctane in good yield (82%), together with minor amounts (2%) of the by-product octenes [46]. In the presence of Cu powder, the activity of the fluorination increased, and it was greatly enhanced by the use of bipyridine.…”