Jump to main content
Jump to site search

Issue 48, 2018
Previous Article Next Article

A unified synthesis of topologically diverse Aspidosperma alkaloids through divergent iminium-trapping

Author affiliations

Abstract

Aspidospermidine, vincadifformine, 1,2-dehydroaspidospermidine, goniomitine, and quebrachamine, five Aspidosperma alkaloids distributed within three structurally diverse topologies, were synthesized from a single molecular scaffold, namely indole–valerolactam 6. This common intermediate can be divergently manipulated, through the incorporation of conformational and electronic constraints that influence the chemo-selectivity of the iminium ion derived therefrom, between three different reaction paths: N(1) vs. C(3) cyclization (indole numbering) vs. over-reduction. Moreover, a catalytic carbene insertion for direct C(3)–H indole functionalization is reported for the first time in an approach to goniomitine (4), and a following tandem ester reduction/iminium generation/cyclization secured its tetracyclic system. The development of a highly diastereoselective one-pot hemi-reduction/cyclization/deprotection process to obtain a cis-pyridocarbazole directly allowed the synthesis of pentacyclic Aspidosperma alkaloids 1, 2, and 3.

Graphical abstract: A unified synthesis of topologically diverse Aspidosperma alkaloids through divergent iminium-trapping

Back to tab navigation

Supplementary files

Publication details

The article was received on 22 Oct 2018, accepted on 20 Nov 2018 and first published on 20 Nov 2018


Article type: Paper
DOI: 10.1039/C8OB02621A
Citation: Org. Biomol. Chem., 2018,16, 9409-9419
  •   Request permissions

    A unified synthesis of topologically diverse Aspidosperma alkaloids through divergent iminium-trapping

    M. V. Mijangos and L. D. Miranda, Org. Biomol. Chem., 2018, 16, 9409
    DOI: 10.1039/C8OB02621A

Search articles by author

Spotlight

Advertisements