Halogen–magnesium exchange of m- and p-iodo or bromo-arenes bearing ortho-directing groups through ate complexes

Abstract

m- or p-Iodinated, or brominated ω-phenoxyalcohols and phenols as well as halogenated indoles were subjected to halogen–magnesium exchange reactions with isopropyl magnesium bromide ( i PrMgBr) or isopropyl magnesium di- n-butyl lithium ate complexes ( i PrMg n Bu 2Li) at −78 °C to room temperature. i PrMg n Bu 2Li proved superior to prevent ortho-metallation of these substituted arenes.