Directed ortho-meta'- and meta-meta'-dimetalations : a template base approach to deprotonation

Martínez-Martínez, Antonio J. and Kennedy, Alan R and Mulvey, Robert E and O'Hara, Charles T (2014) Directed ortho-meta'- and meta-meta'-dimetalations : a template base approach to deprotonation. Science, 346 (6211). pp. 834-837. ISSN 0036-8075

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    Abstract

    The regioselectivity of deprotonation reactions between arene substrates and basic metalating agents is usually governed by the electronic and/or coordinative characteristics of a directing group attached to the benzene ring. Generally, the reaction takes place in the ortho position, adjacent to the substituent. Here, we introduce a protocol by which the metalating agent, a disodium-monomagnesium alkyl-amide, forms a template that extends regioselectivity to more distant arene sites. Depending on the nature of the directing group, ortho-meta' or meta-meta' dimetalation is observed, in the latter case breaking the dogma of ortho metalation. This concept is elaborated through the characterization of both organometallic intermediates and electrophilically quenched products.