Strong bases. Directed ortho-meta'- and meta-meta'-dimetalations: a template base approach to deprotonation.
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.
WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, UK.
Antonio J
AJ
Martínez-Martínez
WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, UK.
Alan R
AR
Kennedy
WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, UK. r.e.mulvey@strath.ac.uk charlie.ohara@strath.ac.uk.
Robert E
RE
Mulvey
WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, UK. r.e.mulvey@strath.ac.uk charlie.ohara@strath.ac.uk.
Charles T
CT
O'Hara