α-Lithiobenzyloxy as a Directed Metalation Group in<i>ortho</i>-Lithiation Reactions
Carlos Sedano, Rocío Velasco, Claudia Feberero, Samuel Suárez‐Pantiga, Roberto Sanz
Abstract
The α-lithiobenzyloxy group, easily generated from aryl benzyl ethers by selective α-lithiation with t-BuLi at low temperature, behaves as a directed metalation group (DMG) providing a direct access to o-lithiophenyl α-lithiobenzyl ethers. This ortho-directing effect is reinforced in substrates bearing an additional methoxy group at the meta position. The generated dianions can be reacted with a selection of electrophiles including carboxylic esters and dihalosilanes or germanes, which afford interesting benzofuran, sila(germa)dihydrobenzofuran, and silachroman derivatives from simple aryl benzyl ethers.
Topics & Concepts
MetalationChemistryElectrophileArylBenzofuranGroup (periodic table)Medicinal chemistryStereochemistryOrganic chemistryAlkylCatalysisCoordination Chemistry and OrganometallicsAsymmetric Synthesis and CatalysisOrganometallic Complex Synthesis and Catalysis