Tremorgenic Indole Alkaloids. 9. Asymmetric Construction of an Advanced F-G-H-Ring Lactone Precursor for the Synthesis of Penitrem D

Amos B. Smith, Ernest G. Nolen, Ryuichi Shirai, Frances R. Blase, Mitsuaki Ohta, Noritaka Chida, Richard A. Hartz, Duke M. Fitch, William M. Clark, Paul A. Sprengeler

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Lactone (+)-12 is envisioned as the precursor to the F—G—H rings of penitrem D (4) in our ongoing synthetic venture. The efficient, stereocontrolled introduction of the vicinal quaternary methyl groups present the major challenge in the construction of this subunit. Our first route to (±)-12 was marked by low overall yield (<2%) and the instability of several key intermediates; these deficiencies weee rectified in a second-generation approach that produced optically active material (18 steps from 19a, 2.1% overall). The successful strategies exploited enolate generation via either conjugate additions to αpha;,β-enones or the Evans oxy-Cope rearrangement as key regiochemical control elements.

Original languageEnglish
Pages (from-to)7837-7848
Number of pages12
JournalJournal of Organic Chemistry
Volume60
Issue number24
DOIs
Publication statusPublished - 1995 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry

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    Smith, A. B., Nolen, E. G., Shirai, R., Blase, F. R., Ohta, M., Chida, N., Hartz, R. A., Fitch, D. M., Clark, W. M., & Sprengeler, P. A. (1995). Tremorgenic Indole Alkaloids. 9. Asymmetric Construction of an Advanced F-G-H-Ring Lactone Precursor for the Synthesis of Penitrem D. Journal of Organic Chemistry, 60(24), 7837-7848. https://doi.org/10.1021/jo00129a025