title: Functionalizations of Mixtures of Regioisomeric Aryllithium Compounds by Selective Trapping with Dichlorozirconocene.
abstract: The reaction of mixtures of aryllithium regioisomers obtained either by directed lithiation or by Br/Li exchange with substoichiometric amounts of Cp2ZrCl2 proceeds with high regioselectivity. The least sterically hindered regioisomeric aryllithium is selectively transmetalated to the corresponding arylzirconium species leaving the more hindered aryllithium ready for various reactions with electrophiles. As an application, these regioselective transmetalations from Li to Zr were used to prepare all three lithiated regioisomers of 1,3-bis(trifluoromethyl)benzene.
authors.affiliation: Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München (Germany).
authors.forename: Alicia
authors.initials: A
authors.lastname: Castelló-Micó
authors.affiliation: Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München (Germany).
authors.forename: Simon A
authors.initials: SA
authors.lastname: Herbert
authors.affiliation: Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München (Germany).
authors.forename: Thierry
authors.initials: T
authors.lastname: León
authors.affiliation: Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München (Germany).
authors.forename: Thomas
authors.initials: T
authors.lastname: Bein
authors.affiliation: Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München (Germany). paul.knochel@cup.uni-muenchen.de.
authors.forename: Paul
authors.initials: P
authors.lastname: Knochel
keywords: lithium; metalation; regioselectivity; transmetalation; zirconium