Heck Arylation of Endocyclic Enecarbamates with Diazonium Salts. Improvements and a Concise Enantioselective Synthesis of (−)-Codonopsinine
journal contributionposted on 07.09.2000, 00:00 by Elias A. Severino, Carlos Roque D. Correia
Total enantioselective synthesis of the natural (−)-codonopsinine was accomplished in seven steps with an overall yield of ∼16% starting from the five-membered endocyclic enecarbamate 4. The total synthesis features a highly efficient and stereoselective Heck arylation of endocyclic enecarbamate 4 with p-methoxybenzenediazonium tetrafluoroborate and a stereoselective epoxidation/epoxide opening sequence as key steps.