title: Surface-assisted diastereoselective Ullmann coupling of bishelicenes.
abstract: Ullmann coupling of chiral 2-bromo[4]helicene has been performed on a Cu(100) surface. Only homochiral 2,2'-bis[4]helicene as the product is observed using STM. Such stereoselectivity is based on the fact that the surface will favour a configuration with the central part of the molecule on the surface, causing the outer ends to spiral away from the surface.
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland. karl-heinz.ernst@empa.ch.
authors.forename: Christian
authors.initials: C
authors.lastname: Wäckerlin
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland. karl-heinz.ernst@empa.ch.
authors.forename: Jingyi
authors.initials: J
authors.lastname: Li
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland. karl-heinz.ernst@empa.ch.
authors.forename: Anaïs
authors.initials: A
authors.lastname: Mairena
authors.affiliation: Laboratoire Moltech Anjou, Université d'Angers, Angers, France.
authors.forename: Kévin
authors.initials: K
authors.lastname: Martin
authors.affiliation: Laboratoire Moltech Anjou, Université d'Angers, Angers, France.
authors.forename: Narcis
authors.initials: N
authors.lastname: Avarvari
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland. karl-heinz.ernst@empa.ch and Department of Chemistry, University of Zurich, Zurich, Switzerland.
authors.forename: Karl-Heinz
authors.identifier: http://orcid.org/0000-0002-2077-4922
authors.initials: KH
authors.lastname: Ernst