18374-17-9Relevant articles and documents
Total syntheses of vincadifformine, 3-oxovincadifformine, pseudo- and 20-epi-pseudovincadifformine, tabersonine, and Δ18-tabersonine through radical reactions and heck reactions
Kuehne, Martin E.,Wang, Tiansheng,Seaton, Pamela J.
, p. 6001 - 6008 (1996)
The pentacyclic alkaloids vincadifformine (9), ψ-vincadifformine (15), and epi-ψ-vincadifformine (16) could be synthesized by intramolecular free-radical-induced cyclizations of the tetracyclic intermediates 7, 8, and 18, which were respectively obtained by condensation of the indoloazepine 1 with 2-(phenylselenyl)butyraldehyde and subsequent Nb-alkylation of the resulting tetracyclic amines 2 and 3, or from condensation of (phenylselenyl)acetaldehyde with the alkylated indoloazepine 17. The intermediates 2 and 3 also gave 3-oxovincadifformine (21) by an intermolecular radical alkylation with methyl acrylate. Their alkylation with (Z)-1,3-diiodopropene, phenyl selenoxide elimination, and intramolecular Heck reactions provided tabersonine (24) and 18,19-didehydrotabersonine (27).
A Concise Synthesis of (+/-)-Vincadifformine and Related Aspidosperma Alkaloids (+/-)-Desethylvincadifformine, (+/-)-Ibophyllidine, (+/-)-20-Epi-ibophyllidine, and (+/-)-Desethylibophyllidine
Barsi, Marie-Christine,Das, Bhupesh C.,Fourrey, Jean-Louis,Sundaramoorthi, Rajeswari
, p. 88 - 89 (1985)
An expeditious total synthesis of (+/-)-vincadifformine (9) and related Aspidosperma alkaloids (+/-)-desethylvincadifformine (10), (+/-)-ibophyllidine (11), (+/-)-20-epi-ibophyllidine (12), and (+/-)-desethylibophyllidine (13) via condensation of a common indole-2-acrylate precursor (2) and an appropriate amine (4) followed by acidic treatment is reported.
A unified synthesis of topologically diverse: Aspidosperma alkaloids through divergent iminium-trapping
Mijangos, Marco V.,Miranda, Luis D.
supporting information, p. 9409 - 9419 (2019/01/03)
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.
Expeditious and Divergent Total Syntheses of Aspidosperma Alkaloids Exploiting Iridium(I)-Catalyzed Generation of Reactive Enamine Intermediates
Tan, Peng Wen,Seayad, Jayasree,Dixon, Darren J.
, p. 13436 - 13440 (2016/10/21)
A new approach for the divergent total syntheses of (±)-vincaminorine, (±)-N-methylquebrachamine, (±)-quebrachamine, (±)-minovine and (±)-vincadifformine, each in less than 10 linear steps starting from a single δ-lactam building block, is reported. Key to our route design is the late-stage generation of reactive enamine functionality from stable indole-linked δ-lactams via a highly chemoselective iridium(I)-catalyzed reduction. The efficiently formed secodine intermediates subsequently undergo either a formal Diels–Alder cycloaddition or a competitive Michael addition/reduction to access aspidosperma-type alkaloids in excellent diastereoselectivities. Product selectivity could be controlled by changing the indole N-protecting group in the reductive cyclization precursors. An asymmetric variant of this synthetic strategy for the synthesis of (+)-20-epi-ibophyllidine is also described.
