title: Structures and ambident reactivities of azolium enolates.
abstract: Oxygen versus carbon: Azolium enolates were generated by the reactions of N-heterocyclic carbenes (NHCs) with methyl phenyl ketene and characterized by X-ray crystallography. Kinetic studies show that the enolate oxygen is 20 times more nucleophilic than the carbon atom, but under thermodynamic control exclusive C-addition products were formed.
authors.affiliation: Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München (Germany) http://www.cup.uni-muenchen.de/oc/mayr. maji.biplab@cup.uni-muenchen.de.
authors.forename: Biplab
authors.initials: B
authors.lastname: Maji
authors.forename: Herbert
authors.initials: H
authors.lastname: Mayr
keywords: N-heterocyclic carbenes; acylazolium ions; kinetics; nucleophilicity; zwitterions