Total synthesis and structural elucidation of azaspiracid-1. Construction of key building blocks for originally proposed structure

J Am Chem Soc. 2006 Feb 22;128(7):2244-57. doi: 10.1021/ja0547477.

Abstract

Syntheses of the three key building blocks (65, 98, and 100) required for the total synthesis of the proposed structure of azaspiracid-1 (1a) are described. Key steps include a TMSOTf-induced ring-closing cascade to form the ABC rings of tetracycle 65, a neodymium-catalyzed internal aminal formation for the construction of intermediate 98, and a Nozaki-Hiyama-Kishi coupling to assemble the required carbon chain of fragment 100. The synthesized fragments, obtained stereoselectively in both their enantiomeric forms, were expected to allow for the construction of all four stereoisomers proposed as possible structures of azaspiracid-1 (1a-d), thus allowing the determination of both the relative and absolute stereochemistry of the natural product.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Crystallography, X-Ray
  • Hydrogen Bonding
  • Marine Toxins / chemical synthesis*
  • Marine Toxins / chemistry
  • Molecular Structure
  • Polyether Toxins
  • Spiro Compounds / chemical synthesis*
  • Spiro Compounds / chemistry
  • Sulfoxides / chemistry

Substances

  • Marine Toxins
  • Spiro Compounds
  • Sulfoxides
  • azaspiracid
  • Polyether Toxins