The preparation and allylation of difluoromethylcadmium

Abstract

The reaction of iodo- and bromodifluoromethane with cadmium powder in DMF at room temperature provides a useful route to difluoromethylcadmium. This partially fluorinated cadmium reagent exhibits excellent thermal stability to temperatures of 65–75 °C, and rapid decomposition does not occur until 105 °C. This reagent reacts readily with allylic halides and shows promise as a new difluoromethylation reagent. The preparation of F -alkyl and F -vinylcadmium reagents has recently received considerable attention [1–13]. These F -cadmium compounds display excellent thermal stability and have been utilized as difluorocarbene, F -alkyl and F -vinyl transfer reagents. The ease of reaction of F -alkyl iodides and bromopentafluorobenzene with cadmium metal [7] prompted us to examine this approach as a method for the preparation of a partially fluorinated cadmium reagent. Our initial interest focused on: (a) the ease of formation of a partially fluorinated cadmium reagent vs . the F -alkyl analog; (b) the stability of this reagent vs . the F -analog; and (c) the reactivity of this reagent vs . the F -analog.