Synthesis of Novel Fluoropicolinate Herbicides by Cascade Cyclization of Fluoroalkyl Alkynylimines

Org Lett. 2015 Jun 19;17(12):2905-7. doi: 10.1021/acs.orglett.5b01176. Epub 2015 May 26.

Abstract

The cascade cyclization of fluoroalkyl alkynylimines with primary amines has been modified to allow the synthesis of 4-amino-5-fluoropicolinates. Use of N-trityl and acetal protecting groups in the cyclization precursor led to 5-fluoropyridines that were easily deprotected to picolinaldehyde derivatives for further elaboration to structures of interest as potential herbicides. This method provided access to picolinic acids with alkyl or aryl substituents at the 6-position that were previously inaccessible via cross-coupling chemistry.

MeSH terms

  • Aminopyridines / chemical synthesis*
  • Aminopyridines / chemistry
  • Cyclization
  • Herbicides / chemical synthesis*
  • Herbicides / chemistry
  • Imines / chemistry*
  • Molecular Structure
  • Picolinic Acids / chemical synthesis*
  • Picolinic Acids / chemistry

Substances

  • Aminopyridines
  • Herbicides
  • Imines
  • Picolinic Acids