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Updated: Jul 6, 2026

In Vitro Biochemical Assays using Biotin Labels to Study Protein-Nucleic Acid Interactions
Published on: July 17, 2019
Nucleophilic beta-oniovinylation: concept, mechanism, scope, and applications
Robert Weiss1, Matthias Bess, Stefan M Huber
1Department of Chemistry and Pharmacy, Organic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestrasse 42, D-91054 Erlangen, Germany. weiss@chemie.uni-erlangen.de
Abstract:
Insertion of an electron-deficient alkyne A-C[triple bond]C-A (A = CO2Me) into the C-L+ bond of an acyl-onio salt R-C(O)-L+ (R = Ar, OAlk; L = 4-dimethylaminopyridine, PPh3) has for the first time been achieved in the presence of catalytic amounts of the nucleophile L. For R = OMe, a second insertion of the alkyne was observed. X-ray structures were obtained for a number of such beta-oniovinylation products. Depending on reaction conditions, preferentially E- or Z-stereochemistry was observed, the Z-isomer being the thermodynamically more stable. A mechanism for this novel insertion reaction is presented which accounts for the topology of the products and rationalizes the observed stereochemistry. The beta-onio-activated Michael systems thus generated represent a virtually unexplored class of compounds. The onio substituent in such compounds can be selectively replaced by a number of nucleophiles. Thus a series of Michael systems with donor functions in the beta-position is easily synthesized. These compounds represent a source for useful further transformations, for example, cyclizations to quinolones, thiochromones, and pyrazoles.
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