Heck arylation of endocyclic enecarbamates with diazonium salts. Improvements and a concise enantioselective synthesis of (-)-codonopsinine.
Total enantioselective synthesis of the natural (-)-codonopsinine was accomplished in seven steps with an overall yield of approximately 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.
Severino
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EA
Instituto de Química, Universidade Estadual de Campinas, UNICAMP, C. P.6154, CEP 13083-970, Campinas, São Paulo, Brazil.
Roque D Correia
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D000478:Alkylation; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D003979:Diazonium Compounds; D011759:Pyrrolidines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D003979:Diazonium Compounds; D011759:Pyrrolidines; C415669:codonopsinine