Enantioselective, Organocatalytic Strategy for the Oxazolomycin Core: Formal Synthesis of (+)-Neooxazolomycin

Org Lett. 2020 Dec 4;22(23):9282-9286. doi: 10.1021/acs.orglett.0c03511. Epub 2020 Nov 23.

Abstract

A concise, organocatalytic, enantioselective route to the γ-lactam core of the oxazolomycins was developed. Key steps include a Lewis base-catalyzed, Michael proton transfer-lactamization organocascade, a one-pot N-methylation and diastereoselective α-alkylation, a diastereotopic group-selective reduction, a substrate-directed allylic hydroxylation, and a lanthanide-mediated organolithium addition to append the side chain. A formal synthesis of (+)-neooxazolomycin via interception of a Kende intermediate, accessed in 10 steps (previously 24 steps from α-d-glucose), enabled confirmation of the relative and absolute stereochemistry.

Publication types

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

MeSH terms

  • Alkylation
  • Bridged Bicyclo Compounds, Heterocyclic / chemical synthesis*
  • Bridged Bicyclo Compounds, Heterocyclic / chemistry
  • Catalysis
  • Molecular Structure
  • Oxazoles / chemical synthesis*
  • Oxazoles / chemistry*
  • Pyrrolidinones / chemistry*
  • Spiro Compounds / chemistry*
  • Stereoisomerism

Substances

  • Bridged Bicyclo Compounds, Heterocyclic
  • Oxazoles
  • Pyrrolidinones
  • Spiro Compounds
  • neooxazolomycin
  • diffusomycin