Vinylogous urethanes in alkaloid synthesis. Applications to the synthesis of racemic indolizidine 209B and its (5 R*, 8 S*, 8a S*)-(±) diastereomer, and to (−)- …

JP Michael, D Gravestock

文献索引：Michael, Joseph P.; Gravestock, David Journal of the Chemical Society, Perkin Transactions 1, 2000 , # 12 p. 1919 - 1928

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被引用次数: 1

摘要

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 ...