An Enantioselective Total Synthesis of (+)-Geissoschizine
1999; American Chemical Society; Volume: 1; Issue: 1 Linguagem: Inglês
10.1021/ol990554a
ISSN1523-7060
AutoresStephen F. Martin, Kevin X. Chen, C. Todd Eary,
Tópico(s)Chemical synthesis and alkaloids
ResumoA concise asymmetric synthesis of the indole alkaloid (+)-geissoschizine (1) has been completed. The synthesis features the highly diastereoselective vinylogous Mannich reaction of 3 with 4 to give 5, which is elaborated into the key tetracyclic intermediate 7 in two steps. Following the stereoselective introduction of the ethylidene moiety to give 9, reduction of the lactam and radical decarboxylation via an acyl selenide gave 12, which was converted into (+)-geissoschizine by formylation. The synthesis requires only 11 chemical operations and proceeds in an overall yield of 17%.
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