NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones

Abstract

Thiazolium carbene-catalyzed reactions of 1,2-diketones and 1,2,3-triketones with enones and ynones have been investigated. The diketones gave α,β-double acylation products via unique Breslow intermediates isolable as acid salts, whereas the triketones formed stable adducts with the NHC instead of the coupling products.

Keywords

• Breslow intermediate
• N-heterocyclic carbene
• ring enlargement
• Stetter reaction
• vicinal polyketone