Enolate-Based Regioselective Anti-Beckmann C–C Bond Cleavage of Ketones

0545341 - ÚOCHB 2022 RIV US eng J - Článek v odborném periodiku
Mašek, Tomáš - Jahn, Ullrich
Enolate-Based Regioselective Anti-Beckmann C–C Bond Cleavage of Ketones.
Journal of Organic Chemistry. Roč. 86, č. 17 (2021), s. 11608-11632. ISSN 0022-3263. E-ISSN 1520-6904
Grant CEP: GA ČR GA13-40188S; GA ČR(CZ) GA19-22085S
Institucionální podpora: RVO:61388963
Klíčová slova: esters * olefins * regioselectivity
Obor OECD: Organic chemistry
Impakt faktor: 4.198, rok: 2021
Způsob publikování: Omezený přístup
https://doi.org/10.1021/acs.joc.1c01169

The Baeyer–Villiger or Beckmann rearrangements are established methods for the cleavage of ketone derivatives under acidic conditions, proceeding for unsymmetrical precursors selectively at the more substituted site. However, the fragmentation regioselectivity cannot be switched and fragmentation at the less-substituted terminus is so far not possible. We report here that the reaction of ketone enolates with commercial alkyl nitrites provides a direct and regioselective way of fragmenting ketones into esters and oximes or ω-hydroxyimino esters, respectively. A comprehensive study of the scope of this reaction with respect to ketone classes and alkyl nitrites is presented. Control over the site of cleavage is gained through regioselective enolate formation by various bases. Oxidation of kinetic enolates of unsymmetrical ketones leads to the otherwise unavailable “anti-Beckmann” cleavage at the less-substituted side chain, while cleavage of thermodynamic enolates of the same ketones represents an alternative to the Baeyer–Villiger oxidation or the Beckmann rearrangement under basic conditions. The method is suited for the transformation of natural products and enables access to orthogonally reactive dicarbonyl compounds.
Trvalý link: http://hdl.handle.net/11104/0322055