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Perkin Transactions 1 ceased publication in 2002. Organic & Biomolecular Chemistry is the RSC's journal for high-quality, original organic chemistry research.
Paper
J. Chem. Soc., Perkin Trans. 1, 2000, 1919 - 1928, DOI: 10.1039/b001853h
Vinylogous urethanes in alkaloid synthesis. Applications to the synthesis of racemic indolizidine 209B and its (5R*,8S
*,8aS*)-(±) diastereomer, and to (–)-indolizidine 209BJoseph P. Michael and David Gravestock
Syntheses of racemic (5R*,8R*,8aS
*)-8-methyl-5-pentylindolizidine (indolizidine 209B) (±)- 1 and its hitherto unknown (5R*,8S*,8aS*) diastereomer (±)- 20 were accomplished in eight steps from pyrrolidine-2-thione and ethyl oct-2-enoate. Key steps included cyclisations exploiting the nucleophilicity of vinylogous urethanes derived from ethyl (2E)-{1-[1-(2-hydroxyethyl)hexyl]pyrrolidin-2-ylidene}acetate 8, and stereoselective reduction of the carbon–carbon double bond of a bicyclic vinylogous urethane 11. An enantioselective modification of the route involving initial conjugate addition of the anion of (R)-(+)-N-benzyl-1-phenylethylamine to tert-butyl (2E)-oct-2-enoate resulted in a formal synthesis of (–)-indolizidine 209B.
