Organocuprate Cross‐Coupling: The Central Role of the Copper(III) Intermediate and the Importance of the Copper(I) Precursor

CuIII in focus: The key intermediate in copper-mediated cross-coupling reactions has long been believed to be a “copper(III) intermediate”. Investigation of reactions of a variety of methyl Gilman reagents Me2CuLi⋅LiX with EtI using rapid-injection NMR spectroscopy conditions reveals a number of formally CuIII tetracoordinate square-planar intermediates (see scheme) with a surprising range of stabilities. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z703035_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.