Modern developments in magnesium reagent chemistry for synthesis

Abstract

Last year (2012) commemorated the 100th anniversary of the award of the Nobel Prize to Victor Grignard for his development of Grignard reagents (at the simplest level expressed as "RMgX", where R is an organic group and X is a halogen), one of the most widely utilised classes of synthetic reagent. A century on but only in the past decade or so has magnesium reagent chemistry entered a new and exciting phase, surpassing the limitations of what traditional Grignard reagents can do. Modern magnesium reagents have been designed to possess essentially comparable reactivity to their great rivals, organolithium reagents (traditional Grignard reagents are orders of magnitude less reactive than organolithium reagents), but at the same time to maintain the superior selectivity and broader functional group tolerance of their traditional ancestors. The key to the design of these new reagents is their multicomponent constitution with the organomagnesium engine powered by an activating alkali-metal additive, often a halide salt or another organometallic entity. This chapter outlines some of the most significant advances in this emerging field. Graphical Abstract: © 2013 Springer-Verlag Berlin Heidelberg.