Stereoselective Total Synthesis of (+)-Aristolactam GI

J Org Chem. 2019 May 3;84(9):5747-5756. doi: 10.1021/acs.joc.9b00653. Epub 2019 Apr 18.

Abstract

Aristolactams are an important subgroup of aporphinoids, which all share a common phenanthrene chromophore motif that is thought to be responsible for the range of interesting physicochemical and biological properties exhibited by these compounds. Among all of the aristolactams discovered, (+)-aristolactam GI displays a unique structural feature of having the aristolactam scaffold linked via a benzodioxane ring to a phenyl propanoid unit, resulting in the compound being an aporphinoid-lignan hybrid. The synthesis of (+)-aristolactam GI was achieved first by synthesis of an orthogonally protected aristolactam, which was prepared using a Suzuki/aldol cascade to convert a differentially protected isoindolin-1-one to the required phenanthrene. The required enantiopure phenyl propanoid unit was prepared from readily available ( R)-methyl lactate. A selective Mitsunobu reaction was used to combine these two key fragments, prior to the formation of the linking benzodioxane in the final step. The absolute stereochemistry of the natural product was confirmed to be 7' S, 8' S.

MeSH terms

  • Chemistry Techniques, Synthetic
  • Heterocyclic Compounds, 4 or More Rings / chemical synthesis*
  • Heterocyclic Compounds, 4 or More Rings / chemistry*
  • Indole Alkaloids / chemical synthesis*
  • Indole Alkaloids / chemistry*
  • Lactams / chemical synthesis*
  • Lactams / chemistry*
  • Stereoisomerism

Substances

  • Heterocyclic Compounds, 4 or More Rings
  • Indole Alkaloids
  • Lactams
  • aristolactam GI