title: From cationic to anionic helicenes: new reactivity through umpolung.
abstract: Using a two-step reduction/metalation procedure, highly stable chiral carbenium ions are transformed into reactive carbanion intermediates. Interesting polar ketone and thioamide products are the results of this umpolung that occurs with complete retention of configuration of the helical backbone.
authors.affiliation: Department of Organic Chemistry, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Conreaux
authors.forename: Nathalie
authors.initials: N
authors.lastname: Mehanna
authors.forename: Christelle
authors.initials: C
authors.lastname: Herse
authors.forename: Jérôme
authors.initials: J
authors.lastname: Lacour