Huang, Xuan Zhu, Tingshun Huang, Zhijian Zhang, Yuexia Jin, Zhichao Zanoni, Giuseppe Chi, Yonggui Robin Carbene-Catalyzed Formal [5 + 5] Reaction for Coumarin Construction and Total Synthesis of Defucogilvocarcins An N-heterocyclic carbene-catalyzed formal [5 + 5] reaction between enals and furanones that generates multisubstituted coumarins in a single step is reported. Five atoms in each of the substrates are involved in this catalytic process to form a benzene and a lactone ring. The power of the method is further demonstrated in metal-free total syntheses of several natural products (defucogilvocarcins M, E, and V) bearing coumarin as the key structural motif. benzene;Coumarin Construction;motif;defucogilvocarcins M;furanone;enal;Carbene-Catalyzed;Defucogilvocarcin;multisubstituted coumarins;method;N-heterocyclic carbene-catalyzed;synthese;lactone ring;substrate;Total Synthesis;metal-free;Formal 2017-11-06
    https://acs.figshare.com/articles/journal_contribution/Carbene-Catalyzed_Formal_5_5_Reaction_for_Coumarin_Construction_and_Total_Synthesis_of_Defucogilvocarcins/5573380
10.1021/acs.orglett.7b03102.s001