Co‐Condensation Reactions of Substituted Aromatic Compounds with Lithium Atoms at 77 K

Abstract

AbstractLithium atoms were co‐condensed with +I‐substituted benzene derivatives like trimethyl(phenyl)silane and tert‐butylbenzene in the presence of THF at 77 K, which resulted in C−H bond activation, to produce the aryllithium compound as well as the coupling of the substituted phenyl radicals. Other +I‐substituted benzene derivatives like xylene and mesitylene failed to react with lithium atoms in the presence of THF. Oxygen and nitrogen donor substituted benzene derivatives (anisole, N,N‐dimethylaniline, and N,N‐dimethylbenzylamine) showed activation of the ortho C−H bond when co‐condensed with lithium atoms in the presence of THF. However, when thioanisole was co‐condensed with lithium atoms and THF, a C−S bond cleavage occurred instead. These results were interpreted with the aid of DFT calculations, which show π‐ and σ‐complexes between the lithium clusters and benzene derivatives as reactive intermediates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)