Plakilactones G and H from a marine sponge. Stereochemical determination of highly flexible systems by quantitative NMR-derived interproton distances combined with quantum mechanical calculations of C-13 chemical shifts

Simone Di Micco, Angela Zampella, Maria Valeria D'Auria, Carmen Festa, Simona De Marino, Raffaele Riccio, Craig P. Butts*, Giuseppe Bifulco

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

23 Citations (Scopus)
217 Downloads (Pure)

Abstract

In this paper the stereostructural investigation of two new oxygenated polyketides, plakilactones G and H, isolated from the marine sponge Plakinastrella mamillaris collected at Fiji Islands, is reported. The stereostructural studies began on plakilactone H by applying an integrated approach of the NOE-based protocol and quantum mechanical calculations of C-13 chemical shifts. In particular, plakilactone H was used as a template to extend the application of NMR-derived interproton distances to a highly flexible molecular system with simultaneous assignment of four non-contiguous stereocenters. Chemical derivatization and quantum mechanical calculations of C-13 on plakilactone G along with a plausible biogenetic interconversion between plakilactone G and plakilactone H allowed us to determine the absolute configuration in this two new oxygenated polyketides.

Original languageEnglish
Pages (from-to)2940-2949
Number of pages10
JournalBeilstein Journal of Organic Chemistry
Volume9
DOIs
Publication statusPublished - 30 Dec 2013

Keywords

  • chemical shift calculations
  • DFT
  • NMR spectroscopy
  • quantitative NOE
  • stereochemical determination of flexible systems
  • DENSITY-FUNCTIONAL METHODS
  • AB-INITIO METHODS
  • COMPUTATIONAL METHODS
  • PLAKINASTRELLA-MAMILLARIS
  • OXYGENATED POLYKETIDES
  • COUPLING-CONSTANTS
  • ORGANIC-MOLECULES
  • NATURAL-PRODUCTS
  • BASIS-SETS
  • SPECTROSCOPY

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