New asymmetric route to bridged indole alkaloids: Formal enantiospecific syntheses of (-)-suaveoline, (-)-raumacline and (-)-Nb-methylraumacline

Patrick D. Bailey, Ian D. Collier, Sean P. Hollinshead, Madeleine H. Moore, Keith M. Morgan, David I. Smith, John M. Vernon

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

The homologous nitrile 13 derived from L-tryptophan undergoes a modified Pictet-Spengler reaction with methyl propynoate, under conditions of kinetic control, to afford the cis-tetrahydro-ß-carboline 15a (cis:trans = 77:23). After protection, Dieckmann-Thorpe cyclisation to the bridged keto nitrile 20 proceeds in 90% yield. Simple functional group modifications via the alcohol 21a and nitrile 22 (structures confirmed by X-ray crystallography) allow convergence with the tetracyclic a,ß-unsaturated aldehyde 10, which is an advanced intermediate for the synthesis of a range of bridged indole alkaloids.

Original languageEnglish
Pages (from-to)1209-1214
Number of pages6
JournalJournal of the Chemical Society, Perkin Transactions 1
Issue number8
Publication statusPublished - 21 Apr 1997

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