The structures of lithium and magnesium organocuprates and related species

Organocuprates are excellent reagents for the formation of carbon–carbon bonds and have been used extensively in synthetic methodology for over fifty years. However, despite their long pedigree the structures, solution behavior, and mechanism of operation of these reagents have often remained opaque. This review concentrates upon the resting-state structures of organocuprates as determined using X-ray crystallographic studies, and provides a comprehensive survey of all solid-state structural characterizations of these species and the intricate nature of their supramolecular assemblies. In addition, solution state experimental data is also presented where it pertains directly to the presented solid-state structures or where it illustrates key points crucial to the understanding of organocuprate reactivity. The structures of all the main classes of organocuprate reagent will be discussed including lithium and magnesium homo-cuprates, cyano-cuprates and hetero-cuprates.