Free radical cyclizations in alkaloid total synthesis: (±)-21- oxogelsemine and (±)-gelsemine

Shogo Atarashi, Joong Kwon Choi, Deok-Chan Ha, David J. Hart, Daniel Kuzmich, Chih Shone Lee, Subban Ramesh, Shung C. Wu

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

Total syntheses of (±)-21-oxogelsemine (3) and (±)-gelsemine (1) are described. Free radical cyclizations play important roles in constructing the tricyclic core (40 → 41) and oxindole (93 → 96) substructures of the target alkaloids, and an isomerization-cyclization strategy (101 → 102) was used to complete construction of the gelsemine cage. Observations made along the way include intramolecular 1,4- and 1,6-hydrogen atom transfers (64 → 65 and 40 → 47) and a free radical cyclization-fragmentation sequence (85 → 86 + 87). A retroaldol-aldol strategy for adjusting oxindole stereochemistry in gelsemine-like structures is also described (72 → 74 and 86 → 87).

Original languageEnglish
Pages (from-to)6226-6241
Number of pages16
JournalJournal of the American Chemical Society
Volume119
Issue number27
DOIs
Publication statusPublished - 1997 Sep 10
Externally publishedYes

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Alkaloids
Cyclization
Free radicals
Free Radicals
Stereochemistry
Isomerization
Hydrogen
Atoms
gelsemine
21-oxogelsemine
oxindole

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Free radical cyclizations in alkaloid total synthesis : (±)-21- oxogelsemine and (±)-gelsemine. / Atarashi, Shogo; Choi, Joong Kwon; Ha, Deok-Chan; Hart, David J.; Kuzmich, Daniel; Lee, Chih Shone; Ramesh, Subban; Wu, Shung C.

In: Journal of the American Chemical Society, Vol. 119, No. 27, 10.09.1997, p. 6226-6241.

Research output: Contribution to journalArticle

Atarashi, S, Choi, JK, Ha, D-C, Hart, DJ, Kuzmich, D, Lee, CS, Ramesh, S & Wu, SC 1997, 'Free radical cyclizations in alkaloid total synthesis: (±)-21- oxogelsemine and (±)-gelsemine', Journal of the American Chemical Society, vol. 119, no. 27, pp. 6226-6241. https://doi.org/10.1021/ja970089h
Atarashi, Shogo ; Choi, Joong Kwon ; Ha, Deok-Chan ; Hart, David J. ; Kuzmich, Daniel ; Lee, Chih Shone ; Ramesh, Subban ; Wu, Shung C. / Free radical cyclizations in alkaloid total synthesis : (±)-21- oxogelsemine and (±)-gelsemine. In: Journal of the American Chemical Society. 1997 ; Vol. 119, No. 27. pp. 6226-6241.
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AU - Lee, Chih Shone

AU - Ramesh, Subban

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