Structural effects in lithiocuprate chemistry: The elucidation of reactive pentametallic complexes

Abstract

TMPLi (TMP=2,2,6,6-tetramethylpiperidide) reacts with CuI salts in the presence of Et2O to give the dimers [{(TMP) 2Cu(X)Li2(OEt2)}2] (X=CN, halide). In contrast, the use of DMPLi (DMP=cis-2,6-dimethylpiperidide) gives an unprecedented structural motif; [{(DMP)2CuLi(OEt2)} 2LiX] (X=halide). This formulation suggests a hitherto unexplored route to the in situ formation of Gilman-type bases that are of proven reactivity in directed ortho cupration. Cu on the other side: A series of new amidocuprates were studied. X-ray crystallography of amidocuprates prepared using copper(I) halides and 2,2,6,6-tetramethylpiperidine revealed Lipshutz-type dimers (see graphic). cis-2,6-Dimethylpiperidine gave a remarkable adduct motif: triangulated, pentametallic amidocuprates based on a lithium halide core. These adducts suggest a new mechanism for forming reactive monomeric Gilman-type cuprate bases. © 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.