Abstract:

Despite of the wide application of organocuprates in many areas of organic synthesis, little is known about their detailed structures in solution. Recently we found by NMR that organocuprates in etheral solution exist as an equilibrium between solvent separated ion pairs (SSIPs) and contact ion pairs (CIPs) with the preference of the equilibrium mainly dependent of the solvent properties, and the CIPs as the reactive species. We focus here on ¹H, ⁶Li and ¹H, ¹H distances investigation by NMR spectroscopy of Me₂CuLi(l) and Me₂CuLi*LiCN (1*LiCN) in Et₂O as models for the structure of salt-free and salt-containing CIPs in solution.