Regio- and chemoselective metalation of arenes and heteroarenes using hindered metal amide bases

Abstract

The preparation of highly functionalized organometallic compounds can be achieved by direct C-H activation of a broad range of unsaturated substrates using lithium chloride solubilized 2,2,6,6-tetramethylpiperidide bases (TMP nMXm·p LiCl). These are excellent reagents for converting a wide range of aromatic and heterocyclic substrates into valuable organometallic reagents with broad applications in organic synthesis. Valuable synthetic intermediates can be obtained by quenching with various electrophiles highly functionalized aryl-, heteroaryl-, and alkenylmetal compounds prepared by direct C-H activation using lithium chloride solubilized 2,2,6,6- tetramethylpiperidide bases, such as TMPMgCl·LiCl, TMPZnCl·LiCl, or TMP2Zn·2 LiCl, which tolerate a wide range of functional groups. The scope and limitations are given for each LiCl-solubilized base. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.