Synthesis of substituted pyridines from cascade [1 + 5] cycloaddition of isonitriles to N-formylmethyl-substituted enamides, aerobic oxidative aromatization, and acyl transfer reaction

J Am Chem Soc. 2013 Mar 27;135(12):4708-11. doi: 10.1021/ja401701x. Epub 2013 Mar 14.

Abstract

A novel strategy for de novo synthesis of pyridines featuring an unprecedented α-addition of aldehyde and enamide to isonitrile as a key step is described. Under mild conditions, a cascade reaction involving Zn(OTf)2-promoted [1 + 5] cycloaddition of isonitrile with N-formylmethyl-substituted enamide, facile aerobic oxidative aromatization and intermolecular acyl transfer from the pyridinium nitrogen to the 5-hydroxy oxygen, and finally acylation of the 4-amino group by an external acyl chloride efficiently afforded 2-substituted 4-acylamino-5-acyloxypyridines in good to excellent yields.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acylation
  • Aldehydes / chemical synthesis
  • Aldehydes / chemistry*
  • Amides / chemical synthesis
  • Amides / chemistry*
  • Cycloaddition Reaction
  • Nitriles / chemical synthesis
  • Nitriles / chemistry*
  • Oxidation-Reduction
  • Pyridines / chemical synthesis*
  • Pyridines / chemistry

Substances

  • Aldehydes
  • Amides
  • Nitriles
  • Pyridines