N-heterocyclic carbene-catalyzed [4 + 2] cycloaddition of ketenes and 3-aroylcoumarins: highly enantioselective synthesis of dihydrocoumarin-fused dihydropyranones

Teng-Yue Jian, Xiang-Yu Chen, Li-Hui Sun, Song Ye
  • Organic & Biomolecular Chemistry, January 2013, Royal Society of Chemistry
  • DOI: 10.1039/c2ob26804c