Interrupting Nazarov Reaction with Different Trapping Modality: Utilizing Potassium Alkynyltrifluoroborate as a σ-Nucleophile

Abstract

The putative oxyallyl cation intermediate generated following Nazarov cyclization of dienone has been successfully intercepted with potassium alkynyltrifluoroborates which act as σ-nucleophiles in the presence of BF3·Et2O. This new trapping modality allowed unprecedented introduction of an alkynyl moiety to the cyclopentanone framework by means of an interrupted Nazarov reaction. The α-alkynyl cyclopentanone product can be further transformed into an array of densely functionalized cyclic compounds.