Chiral N-Heterocyclic Carbenes in Natural Product Synthesis: Application of Ru-Catalyzed Asymmetric Ring-Opening/Cross-Metathesis and Cu-Catalyzed Allylic Alkylation to Total Synthesis of Baconipyrone C

Chiral carbenes as major players: Two recently discovered chiral N‐heterocyclic carbene (NHC) complexes play a crucial role in a concise enantioselective total synthesis of baconipyrone C (see scheme). An (NHC)Cu complex catalyzes a double asymmetric allylic alkylation (AAA), and an (NHC)Ru complex catalyzes an asymmetric ring‐opening/cross‐metathesis (AROM/CM) to establish the absolute configuration of the target. RCM=ring‐closing metathesis.