Iron-catalysed cross-coupling and reduction reactions

Iron nanoparticles of size 6-16 nm have been successfully prepared by the reduction of FeCb with 3-pentylmagnesium bromide in the presence of polyethylene glycol. These nanoparticles show excellent activity in the catalytic dehalogenation of a range of alkyl and aryl halides when used at 5 mol% loadings, if an excess of the Grignard is present to ensure the regeneration of the catalyst. Alkyl halides react to give mixtures of alkane, alkene and homocoupled products, with good selectivity of the alkane product being observed. Aryl halides undergo hydrodehalogenation cleanly and do not undergo homocoupling. A general methodology, previously developed within the group for the cross-coupling of benzyl halides with diarylzinc reagents has been applied to other substrates. This includes 2-halopyridines and N-(bromomethyl)phthalimide, with the former exhibiting slower reaction rates so higher temperatures were required. Surprisingly, in the case of N-(bromomethyl)phthalimide, the coupling reaction was found to proceed without the need for a catalyst. This has been demonstrated for a number of diarylzinc reagents, which resulted in the cross-coupled product being formed in good to excellent yields. Furthermore,. this substrate undergoes cross- coupling with a range of boronic acids via transmetallation to diethylzinc.EThOS - Electronic Theses Online ServiceGBUnited Kingdo