title: Sydnone anions and abnormal N-heterocyclic carbenes of O-ethylsydnones. Characterizations, calculations and catalyses.
abstract: Deprotonated sydnones, which can be represented as anionic N-heterocyclic carbenes, were prepared as Li adducts and compared with deprotonated O-ethylsydnones (5-ethoxy-1,2,3-oxadiazol-4-ylidenes) which belong to the class of abnormal NHCs. The Pd complexes of the sydnone anions (X-ray analysis) as well as of the O-ethylsydnone carbenes proved to be efficient catalysts in aryl couplings of thiophenes.
authors.affiliation: Clausthal University of Technology, Institute of Organic Chemistry, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany. schmidt@ioc.tu-clausthal.de.
authors.forename: Sascha
authors.initials: S
authors.lastname: Wiechmann
authors.forename: Tyll
authors.initials: T
authors.lastname: Freese
authors.forename: Martin H H
authors.initials: MH
authors.lastname: Drafz
authors.forename: Eike G
authors.initials: EG
authors.lastname: Hübner
authors.forename: Jan C
authors.initials: JC
authors.lastname: Namyslo
authors.forename: Martin
authors.initials: M
authors.lastname: Nieger
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmidt