Pd(II)-catalyzed ligand controlled synthesis of pyrazole-4-carboxylates and benzo[b]thiophene-3-carboxylates

Org Biomol Chem. 2014 Nov 21;12(43):8619-26. doi: 10.1039/c4ob01576b.

Abstract

Cyclization-carbonylation of α,β-alkynic hydrazones and (o-alkynylphenyl) (methoxymethyl) sulfides with Pd(tfa)2 in DMSO/MeOH afforded methyl pyrazole-4-carboxylates and benzo[b]thiophene-3-carboxylates, respectively, in good yields. A simple change of the ligand (solvent) allowed controlled, effective switching between cyclization-carbonylation-cyclization-coupling (CCC-coupling) reactions and cyclization-carbonylation reactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carboxylic Acids / chemical synthesis*
  • Catalysis
  • Cations, Divalent
  • Cyclization
  • Dimethyl Sulfoxide / chemistry
  • Hydrazones / chemistry*
  • Ligands
  • Methanol / chemistry
  • Palladium / chemistry*
  • Pyrazoles / chemical synthesis*
  • Thiophenes / chemical synthesis*

Substances

  • Carboxylic Acids
  • Cations, Divalent
  • Hydrazones
  • Ligands
  • Pyrazoles
  • Thiophenes
  • Palladium
  • Methanol
  • Dimethyl Sulfoxide