Novel synthesis of 2-(trifluoromethyl)- and 2-(perfluoroalkyl)-2-hydroxy-2H-chromenes and their regiospecific reaction with silyl enol ethers

J Org Chem. 2006 Oct 27;71(22):8637-40. doi: 10.1021/jo060765a.

Abstract

The synthesis of substituted 2-(trifluoromethyl)- and 2-(perfluoroalkyl)-2-hydroxy-2H-chromenes 2a-o was achieved in good yields by intramolecular cyclization of 3-(perfluoroalkyl)-3-phenoxypropenals 1 in the presence of aluminum chloride. Then a Lewis acid mediated nucleophilic reaction with silyl enol ethers 3 proceeded with complete regiospecificity to afford 4-functional 2-(trifluoromethyl)- and 2-(perfluoroalkyl)-4H-chromenes 4a-p with high yields.

MeSH terms

  • Benzopyrans / chemical synthesis*
  • Benzopyrans / chemistry*
  • Ethers / chemistry*
  • Molecular Structure
  • Stereoisomerism
  • Trimethylsilyl Compounds / chemistry*

Substances

  • Benzopyrans
  • Ethers
  • Trimethylsilyl Compounds