Oxidant free synthesis of α-pyronesviaan NHC-catalyzed [3 + 3] annulation of bromoenals with 2-chloro-1,3-diketones

An NHC-catalyzed [3 + 3] annulation reaction between α-bromo enals and 2-chlorocyclohexane-1,3-diones was developed for the rapid and efficient synthesis of various 4,5,6-trisubstituted α-pyrones, which are core structures in numerous natural products and synthetic bioactive molecules, in generally good to excellent yields.