The target molecular systems tackled by synthetic organic chemists are becoming increasingly more complicated and thus more challenging. For this reason there is a continuing demand for new synthetic methodology. More importantly, any new synthetic methods must meet increasingly stringent criteria in terms of chemoselectivity, regioselectivity and stereoselectivity. Currently major breakthroughs in synthesis are being achieved by the application of organometallic chemistry. In particular, transition metal mediated reactions are becoming recognised as standard components of the organic chemist's repertoire.