The　umpolung　of　alkynyl　1,2-diketones　via　N-heterocyclic　carbene　(NHC)　catalysis　was　achieved　for　the　first　time,　allowing　the　rapid　access　to　a　large　variety　of　synthetically　and　pharmaceutically　important　alpha-pyrones　under　very　mild　conditions.　A　completely　new　NHC-catalyzed　umpolung　pattern　involving　an　O-acylated　allenolate　as　the　key　intermediate　was　proposed.　Moreover,　an　unprecedented　reaction　pathway,　featured　by　a　series　of　group　migrations　and　new　bond　formation,　was　postulated　to　demonstrate　the　formation　of　the　products.